Full opinion text
BRISCOE, Circuit Judge. Defendants Thomas Mower and Leslie Mower appeal their convictions of one count of conspiracy to defraud the United States, in violation of 18 U.S.C. § 371, and six counts of tax evasion, in violation of 26 U.S.C. § 7201, for the years 1992 through 1997. Defendant James Thompson appeals his conviction of one count of conspiracy to defraud the United States, in violation of 18 U.S.C. § 371, and one count of corruptly endeavoring to interfere with the administration of internal revenue laws, in violation of 26 U.S.C. § 7212(a). Thomas Mower argues that (1) the evidence was insufficient to convict him of tax evasion for the years 1992, 1993, and 1997; (2) the district court erred in admitting the government’s summary charts; and (3) the district court erred in compelling Thomas Mower’s attorney, Allen Davis, to testify before the grand jury. Leslie Mower contends that (1) the evidence was insufficient to convict her of all counts; (2) the district court erred in admitting the government’s summary charts; (3) her sentence was procedurally and substantively unreasonable; (4) the district court erred in not giving certain jury instructions; (5) the statute of limitations barred four of the counts of tax evasion, for the years 1992 through 1995; (6) her sentence violated the ex post facto clause; and (7) the district court erred in denying her motion for severance. James Thompson argues that (1) the evidence was insufficient to convict him of either count; (2) the statute of limitations barred both counts; and (3) the district court erred in denying his motion for severance. We exercise jurisdiction under 28 U.S.C. § 1291 and affirm. I. On December 19, 2002, Thomas Mower and his wife, Leslie Mower, were indicted on one count of conspiracy to defraud the United States, in violation of 18 U.S.C. § 371, and six counts of tax evasion, in violation of 26 U.S.C. § 7201, for the tax years 1992 through 1997. On April 8, 2003, the grand jury returned a Superseding Indictment, adding charges against James Thompson for one count of conspiracy to defraud the United States, in violation of 18 U.S.C. § 371, and one count of corruptly endeavoring to interfere with the administration of internal revenue laws, in violation of 26 U.S.C. § 7212(a). Defendants Thomas and Leslie Mower owned three corporations — Neways US, Neways Australia, and Neways Malaysia —each of which utilized a multilevel marketing system to sell a variety of personal care products. In a multilevel marketing system, the company manufactures or purchases product and sells it to distributors, who purchase the product at a discount and make money by selling it to the public at retail price. Distributors receive bonuses by signing up other distributors to sell product. Distributors who have recruited new distributors also receive bonuses as a result of sales by distributors beneath them in the “downline.” Individuals at the top of a Neways downline could make between $25,000 and $35,000 per month. The Mowers had a downline in Neways U.S. called “Base of the Tree,” and a distributorship in Neways U.S. called “Mower Partnership.” Thomas Mower was the president of Neways US, and he was in charge of running the company — “the go-to person.” Neways employees regularly discussed the financial status of the company with him, and he made most of the decisions for Neways US. Randy Lindstrom, a former general manager of Neways US, testified that Thomas Mower had a basic understanding of accounting, as evidenced by their conversations about income and expenses. According to Lindstrom, Thomas Mower “didn’t like to pay taxes.” Leslie Mower also made decisions on a daily basis for Neways US, although she dealt more with distributors than with sales. In the early 1990s, she had virtually no involvement with the financial side of the business. Later, for a period during the mid-1990s, she became Chief Financial Officer of Neways US, even though she did not have any expertise in accounting or finance, and she had some difficulty understanding the company’s financial statements. She would sometimes pay the corporation’s bills, but she mostly just promoted the product. Because of its rapid growth in the early 1990s, Neways U.S. was very heavily indebted to creditors and needed money for operating expenses. The Mowers did not want to borrow working capital from a bank, so they instead tried to solve the company’s money problems by bringing in cash from Neways Australia. Thomas Mower began meeting with his attorneys to determine how to get money out of Neways Australia without paying taxes on it. Soon, Neways U.S. began receiving hundreds of thousands of dollars from Ne-ways Australia, which Neways U.S. recorded as pre-payment for product that it later sent to Neways Australia. In addition to these pre-payments, Neways U.S. received other amounts from Neways Australia that it classified as loans. Neways Australia had two primary bank accounts: an operating account and a bonus checking account. It paid for its day-to-day operations — including bills, payments for product, salaries, and royalty payments to Neways US — from its operating account. Every month, it paid distributor bonuses from the bonus checking account. When examined, the books and records at Neways Australia were found to be in poor condition. At the top of the Neways Australia downline were seven distributorships: Images, Inc. 1 through 7, which later became Neways, Inc. 1 through 7, and then Mower Properties, Inc. 1 through 7. Marija Lee, a former employee at Neways Australia and Neways Malaysia, testified that John Hunter, the then-CEO of Neways Australia, asked her to place these distributorships at the top of the Neways Australia downline. Thomas Mower had originally wanted to set up the Neways Australia downline like the Neways U.S. downline, but John Hunter advised him to create these seven entities to absorb more bonus payments than one entity alone could absorb. These amounts are known in the industry as “breakage.” The Neways 1 through 7 distributorships did not have to sell product to receive commissions, and they were structured to absorb any bonuses that would otherwise flow up to the company itself. Mr. Hunter had several conversations with Thomas Mower regarding Neways 1 through 7, and the need for Neways U.S. to get money from Neways Australia. He assumed the commission payments to Neways 1 through 7 were going to Neways US, because that was why they set up Neways 1 through 7 in the first place. The Neways 1 through 7 entities received commission checks and later, wire transfers, from Neways Australia’s bonus checking account. On its books and records, Neways Australia treated these payments as expenses. Michael Cunningham, a former CEO of Neways Australia, did not know what happened to the commission checks for the Neways 1 through 7 entities after Neways Australia sent the checks to Utah. Marija Lee testified that she sent them to Utah, and none of the checks were ever voided. John Hunter testified that he sent the checks directly to Thomas and Leslie Mower in Utah, although he had no idea what happened to them after they reached the United States. When the checks were late a couple of times, Leslie Mower called Mr. Hunter to ask whether they had been mailed. Once, when the Mowers visited Australia, they asked Mr. Hunter to sign some of the checks over to cash, and he obliged. Neways 1 through 7 distributorships were also set up at the top of the Neways Malaysia downline, and Neways Malaysia sent the commission checks for these distributorships to the United States. At trial, the government introduced commission checks from Neways Malaysia to several of the Neways 1 through 7 distributorships in 1994 and 1995, as well as registers of commission checks from Ne-ways Malaysia for 1996 and 1997. In 1996, the register showed commission checks issued to Neways 1 through 7, as well as Mower Properties 1 through 7, and these entities had the same identification numbers. In 1997, the register showed checks to five other entities with these same identification numbers: Rezults, N. Trust, N. Properties, Eclat, and CC Corp. Patricia Sandberg, Thomas Mower’s former secretary, testified that the Mowers had distributorships in Australia and Malaysia, and she saw checks from these distributorships. Commission checks from Australia and Malaysia arrived once a month through the mail, in envelopes addressed to Thomas Mower personally. A downline report accompanied the checks, and the checks corresponded to amounts on the downline report. Ms. Sandberg understood the commission checks to be from distributorships that the Mowers had in Neways Australia and Neways Malaysia. Usually, she gave the checks to Thomas Mower; sometimes, he gave them back, and she deposited them in an account for “Rezults,” per his instructions. Thomas Mower always had the checkbook for the Rezults account in his possession, and he had signatory authority over the account. Neways U.S. had no records for this account. Ms. Sandberg did not know what the Rezults account was used for, but she thought some of the money may have gone toward the purchase of a warehouse constructed for Neways US. The corporate accounting department at Neways U.S. never saw the commission checks from Australia and Malaysia, never came to ask about them, and never knew that she deposited them. Annette Jenkins, who worked in the accounting department until 1998, testified that, to her knowledge, Ne-ways U.S. never received any commission checks. Patricia Sandberg also identified several commission checks from Neways US, payable to the following people and entities: Thomas Mower; Neways Independent Distributorship Adpool; Base of the Tree; Brett Mower; Lead Allocation, Darrid; MP Trust; Orphanage; MP Enterprises; and BW Enterprises. All of these were endorsed, in some capacity, by Thomas or Leslie Mower, or in Thomas or Leslie Mower’s handwriting. In addition, David Bevans, who worked in the IT department at Neways U.S. in 1996 and 1997, testified that he gave bonus reports to Leslie Mower and that she would sometimes stop by the IT department to pick up distributor checks, asking, “Are my checks ready?” Another entity, Mower Properties, Inc., was the property holding company for Ne-ways US. Neways U.S. leased much of its real property from Mower Properties, including a manufacturing facility, office space, and a warehouse. Karin Lane, who worked in the Neways U.S. accounting department, testified that she did the accounting work for Mower Properties. During the years 1994, 1995, and 1996, the Mower Properties bank account received monies via wire transfer from Neways Australia. Ms. Lane thought they were loans or loan proceeds from Australia, and she treated them as such on Mower Properties’ financial records. Between October 17, 1994, and July 17, 1996, a total of $736,759 was wired from Neways Australia into the Mower Properties account. In 1993 or 1994, the Mowers purchased a property called Hobble Creek. David Simpson, the real estate broker for the transaction, testified that he dealt mostly with Thomas Mower. The purchase price for the property was $650,000, of which the Mowers paid $141,621 as a down payment. They paid the remaining $508,379 of the balance within one year of the purchase. The Mowers paid for the property using checks in U.S., Australian, and Malaysian currency, so the parties to the transaction set up a trust account at First Security Bank. The Mowers would deposit the checks into the trust account, and the bank would convert the amounts to U.S. dollars and issue a new check to the sellers of the property. Almost all of the Mowers’ checks were Australian or Malaysian commission checks payable to the Neways 1 through 7 entities. One of the checks was a U.S. commission check for $54,427.56, payable to Thomas Mower. Mr. Simpson testified that he would pick up the checks from Thomas Mower personally, and not from anyone in corporate accounting at Neways US. The warranty deed for the property stated that the sellers “hereby convey and warrant to Thomas Mower, trustee of the Mower Family Trust.” The Mower Family Trust is a trust controlled by several members of the Mower family, and the Mowers’ personal residence was held by the Mower Family Trust. John Hunter learned about Hobble Creek in 1994. Thomas Mower told him that it was a piece of property they were going to acquire, and he wanted to build a new house on the property, in part because he wanted room to display full-sized animal trophies. Leslie Mower also wanted to move, because she wanted more space for her horses. John Hunter did not know how the property was ultimately used, and he testified that multi-level marketing companies sometimes purchase recreational properties. David Simpson testified that Thomas Mower talked about building a house on the property, although Thomas Mower also stated that he wanted to use the property for corporate retreats and to entertain corporate guests. There was no house on the property at the time of sale, and no house was built after the sale. The property was eventually used for some corporate functions. On March 27, 1997, Agent Elder of the IRS arrived at the Neways U.S. headquarters, looking for Thomas Mower. Patricia Sandberg and Agent Elder testified that Ms. Sandberg was the only person present when Agent Elder arrived, and she told him that Thomas Mower was unavailable. Allen Davis testified, on the other hand, that when the IRS arrived, the legal department was notified, and he went to the lobby with James Thompson to meet with Agent Elder. James Thompson, who was then an attorney for Neways US, told Agent Elder that Thomas Mower was not present — which was untrue — and that they could set up a meeting for a later time. After Agent Elder left, James Thompson and Allen Davis went to Thomas Mower’s office and told him that the IRS was investigating. They informed Thomas Mower that he could either cooperate or refuse to cooperate, and he told them to cooperate. Thomas Mower also told Allen Davis and James Thompson that Hobble Creek might be an issue. Allen Davis and James Thompson began searching the legal and accounting records for documentation of the purchase. They did not find anything, but they knew it had been purchased with funds from Australia. Prior to Agent Elder returning a second time, they called Mr. Cunningham in Australia to try to determine the details of the transaction and whether there was any supporting documentation. Thomas Mower participated in the call. Mr. Cunningham informed them that the monies used to purchase Hobble Creek were commission payments, not a loan. Thomas Mower disagreed with this assessment; he believed that the monies were a loan from Neways Australia and that Neways Australia had recorded them incorrectly. Before Agent Elder returned, Allen Davis, James Thompson, and Thomas Mower discussed whether there was any documentation of a loan from Neways Australia for the purchase of Hobble Creek. When they could find none, James Thompson decided to create a document to support the loan. The document that he created, however, was back-dated to January 6, 1994. Thomas Mower signed the loan document, which stated that Neways Australia had loaned $650,000 to the Mower Family Trust for the purchase of Hobble Creek. When Agent Elder returned, he met with Thomas Mower, Allen Davis, and James Thompson. Thomas Mower told Agent Elder that he did not have any distributorships in the Neways U.S. down-line. He told Agent Elder that he did not receive any checks for any distributorships, and that he left with the company any monies to which he might be entitled. He also stated that he did not know what MP Trust was. Although Thomas Mower disclosed several individual and corporate bank accounts to Agent Elder, he did not mention the Rezults account. Thomas Mower also told Agent Elder that Hobble Creek had been purchased with a loan from Neways Australia. When Agent Elder asked for documentation, James Thompson and Allen Davis left the room to retrieve the newly created loan document. Upon their return, James Thompson handed a folder to Thomas Mower, who reviewed the loan document and handed the folder to Agent Elder. No one told Agent Elder that the loan document was back-dated. Allen Davis later told Leslie Mower about the back-dated loan document, and he continued to keep Leslie Mower apprised of the situation, although she was not directly involved in it. After the meeting, Allen Davis and James Thompson continued searching for documentation, and they attempted to gather additional information from the accounting department and Neways Australia. They continued to have phone conversations with Michael Cunningham in Australia, and they kept Leslie Mower apprised of what was happening. They verified that Neways Australia had treated the Hobble Creek monies as commission payments, rather than as a loan. They determined that, because the property was in the name of the Mower Family Trust, and because they believed that Thomas Mower was the payee on the commission checks, the income was personal income to the Mowers, and the Mowers needed to amend their individual income tax returns. For his part, Agent Elder traveled to Australia to investigate the payments made by Neways Australia. Thomas Mower gave him permission to review the books of Neways Australia, but no one informed Agent Elder that there was actually no Hobble Creek loan. On October 31, 1997, Allen Davis wrote a letter to Agent Elder, informing him that Neways Australia had not properly recorded the money as a loan, and that they were amending the Neways U.S. corporate tax returns to reflect the amounts. This letter was the first time anyone informed Agent Elder that Neways Australia might not have recorded these monies as a loan, or that Hobble Creek was an asset of Neways U.S. rather than the Mower Family Trust. During his investigation at Neways Australia, Agent Elder found no evidence that a loan had been made to anyone — including the Mower Family Trust, Mower Properties, or the Mowers personally. When he returned from Australia, he told Allen Davis that Neways Australia had not recorded the payments as a loan. He also interviewed Leslie Mower sometime in 1998, and she told him that she directed the financial operations of Neways U.S. and that anything financial at Neways U.S. would have to go through her. Meanwhile, in the aftermath of the meeting with Agent Elder, James Thompson contacted Agent Elder and left two telephone messages on his answering machine. The first was on April 4, 1997, and stated: Hello, this is James Thompson, calling, uh ... uh ... on behalf of Tom Mower, uh ... we have been going through documents and-and things that ... trying to get whatever else might be available in this matter. Uhm, I thought I should call you and just talk to you. Basically to let you know that, uhm ... uh ... we have been unable to find anything new, uhm ... I’m not sure what we would be looking for new. Uhm, I believe you have everything, uhm ... apparently what happened, what you thought happened did happen, uh, the checks came, uhm ... he signed them over directly, uh-uhm ... got the loan from the, uh ... Australian organization and, uh ... must pay that back, uh ... within five years thereof, I believe that answers all your questions, uhm ... we’ve gone through everything and haven’t been able to find anything more. So ... I’m not sure what more we would be looking for at this point. But if there’s something specifically ... uh, that you want us to find on that deal, let us know, but-but actually that pretty much covers it, I think. So, if you’ll call me back at four two three twenty-eight hundred (423-2800), again, this is James Thompson and, uh ... and we’ll see where we need to go. Okay? Thanks a lot, bye-bye. Tr. at 705-09; Gov’t Ex. 21-5, 21-5A. The second message was on April 8, 1997, and stated: Hi, Ted. James Thompson here. Uhm ... I was just looking over the file again, uh ... we’ve been running around seeing if we can’t find anymore documents and we’ve been unable to do so ... uh, just like the message I left you the other day. I’m not sure what else that-that we might be looking for that would interest you. Uhm ... so far we just have not found any other documents. So, if you could let me know what you prefer as you know we’re ... we have several summonses that, uh ... that would be quite burdensome if we tried to produce all of that information and you did mention there were other properties that you might be interested in getting information on, but as I understood it, as you left, really you wanted to focus on the Hobble Creek property and so that’s what we’ve been focusing on and I got the feeling from you that ... that if you were satisfied, uhm ... about the facts surrounding that, that you wouldn’t ... that you wouldn’t really care to, uh ... make us dig into everything else, uh ... so I haven’t, I haven’t dug into anything else yet. But I wanted you to know that I’m not just ignoring you, that, uh ... that I want to do whatever you ... want to do on this. Because you’re within your right to ask for certain information, but, uh ... just because of the burden, I hope to avoid it. So, you let me know if you would. I’m, again, James Thompson at four two three twenty-eight hundred (423-2800). Uh, and again ... I assume, you know, this is the ... uh ... (CHUCKLES) ... the Tom Mower matter and, uh ... if there’s anything I can do, let me know, but I don’t want to just keep you hanging out there, all right? Thanks a lot. Bye-bye. Tr. at 705-09; Gov’t Ex. 21-5, 21-5A. Agent Elder testified that he viewed these messages as an attempt by James Thompson to represent that they had given him everything, and that he did not need to investigate further. For his part, Michael Cunningham testified that he participated in a conference call with Thomas Mower, Allen Davis, and Karin Lane, in which Thomas Mower asked Mr. Cunningham if Neways Australia had any documentation for a loan from the Mowers to Neways Australia. Ms. Lane also sent a fax to Neways Australia on October 13,1997, inquiring as to whether they had found any documentation for a loan. John Dwyer, an in-house accountant at Neways Australia, prepared a response, dated October 17,1997, in which he stated: All payments from [Neways Australia] to Thomas Mower are for BONUSES for the Mower downline paid from the MLM system. To my knowledge no Loan was made to Neways Australia and the majority of the payments listed were not Loan repayments but are BONUS payments for the Mower Australian downline. Tr. at 213, 215, 421-22; Gov’t Ex. 20-13. In addition, Mr. Cunningham testified that he was not aware of any loans between Neways Australia and the Mowers personally, or between Neways Australia and the Mower Family Trust or Mower Properties. John Hunter similarly testified that Ne-ways Australia never loaned money to the Mowers individually, or to the Mower Family Trust, Mower Properties, or Neways 1 through 7. Moreover, Mr. Hunter testified that Neways Australia would not have made loan payments with commission checks. Karin Lane likewise testified about the conference call and the alleged loan. Part of the conference call dealt with the characterization of the monies wired to the Mower Properties account. She originally thought that these were loan proceeds, but Mr. Cunningham told her that they were distributor income. She realized that she had incorrectly characterized the monies on Mower Properties’ tax returns and that she would have to amend the returns. However, the returns were never amended. After Ms. Lane received the fax from John Dwyer, she decided to amend the Mowers’ individual income tax returns to include the monies wired to the Mower Properties account. These monies included $44,209.59 in 1994, $449,095.13 in 1995, and $328,593.15 in 1996, for a total of approximately $821,897. Ms. Lane also found a check for $54,427, dated March 20, 1994, and payable to Thomas Mower, which she included in the Mowers’ income. From this information, a hired accounting firm prepared 1040Xs for the years 1994, 1995, and 1996, stating that the Mowers’ owed $39,220, $181,177, and $128,841 in taxes, penalties, and interest for those years, respectively. A later review by the IRS indicated that the amended returns primarily addressed payments made to the Mower Properties account. The Mowers, however, never filed the amended individual income tax returns. Thomas Mower decided not to file them, and Allen Davis told Karin Lane that the beneficiary of the monies was actually Ne-ways US, and not Mower Properties or the Mowers personally. Allen Davis testified that he had originally thought that Thomas Mower was the payee on the commission checks. This was actually not the case, and when Allen Davis discovered that the payees were the Neways 1 through 7 entities, he recommended to Thomas Mower that the Mowers not file the amended individual returns. Instead, Thomas Mower decided to file amended corporate returns for Neways US, reporting additional income of $283,934.30 for 1994 and $247,233.18 for 1995. They filed the returns in early 1998, and paid the taxes, penalties, and interest owing on the additional income. Thomas Mower remained adamant, though, that the monies were loans and not commissions. Allen Davis informed Leslie Mower about these decisions, and she signed amended corporate returns for Neways U.S. on January 6, 1998. Karin Lane testified that, even though certain monies were wired directly into the Mower Properties account, they submitted the amended corporate tax returns for Ne-ways U.S. to account for these monies because Neways U.S. was the actual beneficiary — and the amounts were loans from Neways U.S. to Mower Properties. When she filed the amended returns for Neways US, Karin Lane did not yet know about certain other monies. For instance, she did not know about the Rezults account. She did not know about Hobble Creek. She did not know about the commission checks from Neways Malaysia or from Ne-ways Australia. Eventually, when she found out about Rezults and Hobble Creek, she had to ask the accounting firm to prepare another set of amended returns. Finally, Ms. Lane testified that, when she was preparing the Mowers’ individual income tax returns, Leslie Mower informed her that the Mowers had a down-line called MP Trust, listed under Thomas Mower’s Social Security number. Leslie Mower told Karin Lane that the Mowers received monies from MP Enterprises, Base of the Tree, Revenol, Employee Purchases, BP Sales, and BW Enterprises. Additionally, Ms. Lane discovered that sometimes the Mowers would not cash their distributor checks, particularly if the company was having money troubles, and the Mowers paid some of Neways US’s and Mower Properties’ bills from the Mowers’ personal checking account. Ms. Lane also testified that the Mowers had loaned a lot of money to Mower Properties, that the accounting staff knew about these monies and treated them as loans, and that, when the Mowers received payments from Mower Properties, the payment amounts were subtracted from the loan amounts. Ms. Lane identified several checks and deposited items, payable to Thomas Mower or MP Trust, that had been deposited in the Mower Properties account and had been treated as loans from the Mowers to Mower Properties. These deposits totaled $411,536.91 from 1994 to 1997. Ms. Lane admitted, though, that other deposits into the Mower Properties account during the same time period were commission income that no one had reported. The government devoted substantial time at trial to the testimony of its expert, IRS Agent Renae Trask. Agent Trask compiled checks, deposit slips, and bank records, and she created summaries of all of the commission checks that the government could discover and that the government alleged were personal income to the Mowers. At least one piece of evidence supported each item listed on the summaries, and she converted amounts in Australian or Malaysian currency to U.S. dollars using the conversion rate at the time of each transaction. Exhibit 81-1 listed all of the checks and wire transfers that the government had been able to discover, and it included all of the information from each transaction: the check date, payor, check number, payee, amount (in U.S. dollars), disposition (if known), disposition date, endorsement (if any), and exhibit number. Exhibit 80-3 summarized all of the amounts by year and listed the total commission income for each year from each country, the commissions reported by the Mowers on their tax returns, and the total unreported commissions. Agent Trask testified that, in creating this exhibit, she assumed the commissions were the Mowers’ personal income. She believed this was a valid assumption for many reasons, including: (1) Thomas Mower originally wanted the Neways Australia commission checks made out to him personally, and John Hunter suggested the Neways 1 through 7 entities as an alternative; (2) all of the Neways 1 through 7 checks were pulled and sent to Utah, addressed to the attention of Thomas and Leslie Mower; (3) the Neways U.S. accounting department was unaware of these checks; (4) Hobble Creek was purchased with these funds, and it was owned by the Mower Family Trust; (5) all of the funds were disposed of at Thomas Mower’s direction; (6) no one at Neways U.S. knew this money existed until the IRS began investigating in 1997; (7) John Dwyer’s letter stated that these were “BONUSES for the Mower down-line”; (8) these were clearly commission checks, and not loans; and (9) John Hunter personally handed some checks to the Mowers and signed them over to cash. For 1992, she calculated the unreported commissions to be $179,362; for 1993, $512,606; for 1994, $1,028,455; for 1995, $555,648; for 1996, $536,711; and for 1997, $397,033. The unreported commissions totaled $3,209,815. In 1996 alone, the Mowers reported only half of the commission income that they received from Neways US, and none of the commission income that they received from either Neways Australia or Neways Malaysia. Ultimately, Agent Trask calculated the total tax due and owing as $1,262,081. Other exhibits detailed specific dispositions of commission checks. Exhibit 81-5 summarized a series of deposits on July 27, 1994, into Leslie Mower’s savings account, all from checks dated June 20, 1994, and made out to Neways 2, 4, 5, 6, and 7. These amounts totaled $55,302.83. Agent Trask did not believe that the Mowers had made a mistake in depositing these amounts in Leslie Mower’s savings account, although the defendants introduced evidence showing that, in January 1995, the Mowers transferred $20,000 from this account into the Mower Properties checking account and $40,000 from this account into the Neways U.S. corporate account. Exhibit 100-1 showed how the payee names on the commission checks changed over time from 1992 to 1998. Many of the entities listed as payees on the commission checks — including Neways Independent Distributor Ad Pool, Base of the Tree, MP Enterprises, BP Sales International, BW Enterprises, Rezults, and the Mower Family Trust — had never paid federal taxes. Moreover, two bank accounts — the Mowers’ personal checking account and the Rezults account — had been opened using Social Security numbers for two of the Mowers’ children. Exhibits 100-2 and 100-3 summarized the disposition of the Neways Australia and Neways Malaysia checks, respectively, between 1994 and 1997. Exhibit 100-4 summarized all commission income from all three entities — Neways US, Neways Australia, and Neways Malaysia — between 1992 and 1997. A total of $712,111 was listed as “unknown” on the summary, and it consisted mostly of Australian commission checks for which the government did not know the ultimate disposition. Of the approximately $2.3 million in commission income from Neways Australia between 1992 and 1997, no person or entity reported any of it before the IRS began investigating. At the close of the government’s evidence, the defendants moved for a judgment of acquittal under Fed.R.Crim.P. 29, but the district court denied the motion. The defendants then called two witnesses: Wade Winegar, a former general counsel at Neways US, and E. Gail Anger, an expert witness. Mr. Winegar testified that, when he began working in the legal department at Neways U.S. in 1999, he found a lot of corporate structures that various people had set up over the years, and the Mowers did not understand this set up — they just followed their attorneys’ advice. The Mowers viewed all of the structures as one “big ball of wax,” and they did not view the corporate structures as separate legal entities. Money flowed freely between the different corporations, and although these transfers should have been treated as inter-company loans, no documentation supported this treatment. The Mowers had intended Mower Properties to be a real estate holding company for all of the other companies, and Mower Properties paid the property taxes on the different properties. The Mowers, though, had not run Mower Properties as a separate legal entity, and the properties had been titled in many different names. As for Hobble Creek, Mr. Winegar testified that he gathered information about the property and was told that it was a retreat for Neways US, where the company would host distributors and customers. He found verification, including pictures and videotapes in the marketing department at Neways US, and he saw plans for a distributor lodge on Hobble Creek. John Dwyer told him that the checks used to purchase Hobble Creek had come from a payment stream assigned to Mower Properties. A number of payment streams came from Neways Australia, and people at Neways U.S. kept getting confused about whether payments were distributor commissions or pre-payments for product. Also, Hobble Creek was kept on the books of Mower Properties, although Mr. Winegar admitted that it did not appear on Mower Properties’ financial statements for 1993, 1994, 1995, or 1996. In 2003, Mr. Winegar re-titled Hobble Creek from the Mower Family Trust to Mower Properties. The defendants’ expert, E. Gail Anger, worked to rebut the testimony of Agent Trask. He disagreed with Agent Trask’s conclusion that the commissions were personal income to the Mowers. He stated that nothing in the bonus histories indicated that the Hobble Creek monies were personal to the Mowers, and just because the checks were sent to the Mowers in Utah, and the property was titled in the name of the Mower Family Trust, did not make the Hobble Creek monies personal income. According to Mr. Anger, Mower Properties had “the burdens and benefits of ownership,” and Hobble Creek was therefore corporate property. The great bulk of the checks, from Neways Australia and Neways Malaysia, moreover, were not payable to the Mowers personally. In addition, the unidentified checks were never negotiated, and most of the expenses paid out of the Rezults account were corporate expenses. Mr. Anger also testified that, eventually, all of the unreported items identified by the government — except the checks that were not negotiated — were reported on amended corporate income tax returns for the various companies. On cross-examination, though, Mr. Anger admitted that Agent Trask had “a reasonable argument,” even if he disagreed with her. He also admitted that no one ever reported any of the $3.2 million in any originally filed tax returns, and that Neways U.S. should not have been the entity amending its returns if the income was the income of Mower Properties. Further, he admitted that the accountants at Neways U.S. should have known about the money if it was corporate income. At the close of the evidence, the defendants renewed their motions for acquittal, which the district court denied. After the jury was instructed and the case submitted, the jury found all three defendants guilty on all counts. Subsequently, Thomas Mower and Leslie Mower renewed their motions for acquittal, or in the alternative, for a new trial, and James Thompson renewed his motion for acquittal. The district court denied the motions. Prior to sentencing, the district court held a hearing pursuant to U.S.S.G. § 6A1.3, at which the parties presented their proposed tax loss findings for sentencing. The district court then issued its tax loss findings. After detailing the evidence and its own findings of fact, the district court calculated Thomas Mower’s tax loss to be $199,775. Under U.S.S.G. § 2T4.1 (2005), the base level for this tax loss amount was 16. The district court calculated Leslie Mower’s tax loss to be $89,112, which also resulted in a base level of 16 under U.S.S.G. § 2T4.1 (2005). At the sentencing hearing on September 13, 2006, the district court sentenced Thomas Mower first. The district court determined that there were overt acts after 2001, so the 2001 Guidelines applied. The court increased Thomas Mower’s base level by 2 for sophisticated means, see U.S.S.G. § 2T1.1(b)(2), and by 2 for playing a leading role, see U.S.S.G. § 3B 1.1(c), for a total offense level of 20. Combined with a criminal history category of I, this yielded a Guidelines range of 33 to 41 months, and the district court sentenced Thomas Mower to 33 months’ imprisonment, followed by 36 months of supervised release. The district court also applied the 2001 Guidelines for Leslie Mower, despite her counsel’s argument that the 1997 Guidelines were appropriate. The court increased her base level by 2 for sophisticated means, see U.S.S.G. § 2T1.1(b)(2), resulting in a total offense level of 18, which combined with a criminal history category of I for a Guidelines range of 27 to 33 months. The district court sentenced her to 27 months’ imprisonment, followed by 36 months of supervised release. Lastly, the district court sentenced James Thompson to a term of imprisonment for 12 months and a day, followed by 24 months of supervised release. II. Sufficiency of the evidence On appeal, all three defendants challenge the sufficiency of the evidence to support their convictions. Thomas Mower challenges the sufficiency of the evidence as to his conviction for tax evasion for the years 1992, 1993, and 1997. Leslie Mower challenges the sufficiency of the evidence as to all counts — conspiracy to defraud the United States, and tax evasion for the years 1992 through 1997. James Thompson challenges the sufficiency of the evidence as to both counts — conspiracy to defraud the United States, and corruptly endeavoring to interfere with the administration of internal revenue laws. ‘“Evidence is sufficient to support a conviction if a reasonable jury could find the defendant guilty beyond a reasonable doubt, given the direct and circumstantial evidence, along with reasonable inferences therefrom, taken in a light most favorable to the government.’ ” United States v. Nelson, 383 F.3d 1227, 1229 (10th Cir.2004) (quoting United States v. Wilson, 107 F.3d 774, 778 (10th Cir.1997)). “We will not weigh conflicting evidence or second-guess the fact-finding decisions of the jury.” United States v. Summers, 414 F.3d 1287, 1293 (10th Cir.2005). “Rather than examining the evidence in ‘bits and pieces,’ we evaluate the sufficiency of the evidence by ‘considering the collective inferences to be drawn from the evidence as a whole.’ ” Nelson, 383 F.3d at 1229 (quoting Wilson, 107 F.3d at 778). As a preliminary matter, both Thomas and Leslie Mower rely heavily on the district court’s tax loss findings at sentencing in attacking the sufficiency of the evidence to support their convictions. The tax loss findings, however, do not alter our sufficiency review for three reasons. First, the district court’s determination of a tax loss for sentencing purposes and the jury’s determination of guilt based upon the sufficiency of the evidence are different and distinct inquiries. See, e.g., United States v. Greene, 239 Fed.Appx. 431, 447 (10th Cir.2007) (rejecting the defendant’s argument that the district court was prohibited from calculating the tax loss based upon facts found at sentencing); United States v. Kosinski, 480 F.3d 769, 776 (6th Cir.2007). Granted, in most instances, this distinction becomes relevant where a district court has calculated a greater tax loss than that found by the jury at trial, but there is no reason to blur the two inquiries when the converse situation is presented. Cf. United States v. Scholl, 166 F.3d 964, 981 (9th Cir.1999) (holding that the district court did not err in finding, during sentencing, that “there was insufficient evidence to make a reasonable estimate of tax loss,” where the jury convicted the defendant of violating 26 U.S.C. § 7206(1)). Second, in the instant case, the district court denied the Mowers’ respective post-verdict motions for judgment of acquittal, indicating the district court thought that the evidence was sufficient to support the jury’s verdicts, notwithstanding the district court’s later tax loss findings. Third, given the evidence outlined above, the district court would have been justified in calculating a greater tax loss than it did. In analyzing the Mowers’ sufficiency of the evidence claims, therefore, we will disregard the district court’s tax loss findings and employ our usual sufficiency of the evidence analysis by reviewing the evidence presented at trial to determine “if a reasonable jury could find the defendant guilty beyond a reasonable doubt, given the direct and circumstantial evidence, along with reasonable inferences therefrom, taken in a light most favorable to the government.” Nelson, 383 F.3d at 1229 (citation and internal quotation marks omitted). A. Thomas Mower The evidence was sufficient to convict Thomas Mower of tax evasion for the years 1992, 1993, and 1997. He has chosen to appeal these years — and not 1994, 1995, and 1996 — because in 1992, 1993, and 1997, the only alleged unreported income was foreign commission income, as opposed to a combination of domestic and foreign commission income. “In order to prove a defendant guilty of tax evasion, the government must show (1) a substantial tax liability, (2) willfulness, and (3) an affirmative act constituting evasion or attempted evasion.” United States v. Anderson, 319 F.3d 1218, 1219 (10th Cir.2003); see also 26 U.S.C. § 7201 (“Any person who willfully attempts in any manner to evade or defeat any tax imposed by this title or the payment thereof shall ... be guilty of a felony....”). In proving tax evasion, the government’s evidence is ordinarily circumstantial, since direct proof is often unavailable. Circumstantial evidence in this context may consist of, among other things, a failure to report a substantial amount of income, a consistent pattern of underreporting large amounts of income, the spending of large amounts of cash that cannot be reconciled with the amount of reported income, or any conduct, the likely effect of which would be to mislead or to conceal. United States v. Kim, 884 F.2d 189, 192 (5th Cir.1989) (citations and internal quotation marks omitted). A reasonable jury could have found beyond a reasonable doubt that Thomas Mower had a substantial tax liability for the years 1992, 1993, and 1997. In 1992, several Australian checks, payable to Images 1 through 7, were drawn on the Australian National Bank. One of these checks contained a handwritten note on the front with the words, “Please Pay Cash.” John Hunter testified that, when the Mowers visited Australia, they once asked him to sign commission checks over to cash, and he obliged. In addition, the government discovered multiple commission checks from 1992 that had an “unknown disposition.” Although the Mowers presented evidence at trial that these checks were not negotiated, the receipt of the checks — and not their negotiation — is the important fact in determining whether income is taxable in a given year. See Walter v. United States, 148 F.3d 1027, 1028-29 (8th Cir.1998) (explaining, under the theory of constructive receipt, that a lost check was still taxable in the year it was received, even though the defendants did not obtain or cash a replacement check until two years later); see also 26 C.F.R. 1.451-2. For the doctrine of constructive receipt to apply, the checks must have been personal income to the Mowers, but as explained below, there was more than enough evidence for a reasonable jury to conclude that they were. As regards 1993,' the government produced evidence of a variety of foreign commission checks with a variety of dispositions. Several of the checks were endorsed directly to pay for Hobble Creek. Others were deposited in the Rezults account. Multiple foreign commission checks from 1993 had an “unknown disposition.” In 1997, a number of foreign commission checks were deposited in the Mower Properties account, the Rezults account, and the Neways U.S. account. Most importantly, the evidence indicated that the foreign commission checks were personal income to the Mowers. Thomas Mower originally wanted the Ne-ways Australia commission checks made out to him personally, and he only created the Neways 1 through 7 entities after John Hunter suggested it. All of the foreign commission checks were pulled and sent to Utah, addressed to the attention of Thomas Mower. No one in the corporate accounting department at Neways U.S. was aware of the checks until after the IRS began investigating in 1997. John Hunter personally signed several of the commission checks over to cash and handed them to the Mowers, and one of the 1992 commission checks has “Please Pay Cash” on the front of it. All of the funds were disposed of at Thomas Mower’s direction. No one at Neways US — except for the Mowers and Thomas Mower’s secretary— knew of the Rezults account, and the Mowers had control over the account. Several of the checks from 1993 were endorsed directly to pay for Hobble Creek, which was titled in the name of the Mower Family Trust and was where the Mowers had planned to build a house. Further, no one at Neways U.S. knew about Hobble Creek until after the IRS became involved. Even the false loan document stated that the “loan” for Hobble Creek was to the Mower Family Trust, not to any of the corporations. John Dwyer’s letter stated that these were “BONUSES for the Mower downline.” Also, despite the Mowers’ insistence that these were loans or loan repayments, they were clearly commission checks, and the evidence showed that when the Mowers needed a loan for Ne-ways U.S. from Neways Australia, they knew how to accomplish it — and how to include it on the books of both companies. Most significantly, despite the Mowers’ insistence that these monies were corporate income, and not personal income, no person or entity paid any taxes on the $2,384,849 of Australian commission income or the $324,554 of Malaysian commission income until after the IRS began investigating in 1997. Finally, the Mowers continually changed their story as to what these commission checks actually were— loans from Neways Australia, loan repayments from Neways Australia, income to Neways US, income to Mower Properties, etc. Taken together, the evidence was more than sufficient for the jury to find beyond a reasonable doubt that the commission checks were personal income to the Mowers, for which they incurred a “substantial tax liability.” Anderson, 319 F.3d at 1219. Additional evidence — and much of the evidence listed above — showed that Thomas Mower’s failure to report these monies was “willful[].” Id. Asking John Hunter to endorse checks directly to cash shows willfulness as to the 1992 amounts. In addition, Thomas Mower endorsed checks directly to purchase Hobble Creek in 1993, and he presented a false, backdated loan document to the IRS in an effort to cover up the purchase. He lied to Agent Elder about not having a distributorship in Neways US. Further, the sheer number of shell corporations and entities that the Mowers created here — and which were payees for the various commission checks — is nothing short of astounding, as is the number of different payees indicated on the commission checks, as well as the number of different accounts in which the Mowers deposited all of the commission checks. Along these same lines, the Mowers frequently opened bank accounts under incorrect Social Security or employer identification numbers. From this circumstantial evidence, a reasonable jury could have found beyond a reasonable doubt that Thomas Mower’s failure to report these amounts was willful. Finally, the evidence showed affirmative acts of evasion for each year. “An affirmative act requires more than the passive failure to file a tax return; rather, it requires a positive act of commission designed to mislead or conceal.” United States v. Meek, 998 F.2d 776, 779 (10th Cir.1993). The government only needed to show one affirmative act of evasion for each count of tax evasion, see Anderson, 319 F.3d at 1219; Meek, 998 F.2d at 779, and here, many of the affirmative acts of evasion related to multiple years. For instance, the creation and presentation of the false, back-dated loan document certainly qualifies as an affirmative act of evasion — arguably for all six years of tax evasion, and at the very least for 1993 and 1994. Later, and long after the IRS began investigating, the Mowers had Neways U.S. file several sets of amended corporate returns, in which they attempted to claim that the commissions were actually corporate income, rather than personal income. A reasonable jury could have found beyond a reasonable doubt that these were affirmative acts of evasion as to the foreign commission checks issued in 1992, 1993, and 1997. In his argument on appeal, Thomas Mower contends that the evidence did not comport with the government’s use of the “specific items method” of proving tax evasion. Under the specific items method, “the Government ... produce[s] evidence of the receipt of specific items of reportable income by the defendant that do not appear on his income tax return or appear in diminished amount.” United States v. Horton, 526 F.2d 884, 886 (5th Cir.1976) (contrasting this with the “net worth method,” whereby the government shows an “increase in the taxpayer’s net worth during the period in question in an amount greater than that reported to IRS”); see also United States v. Merrick, 464 F.2d 1087, 1092 (10th Cir.1972). Contrary to Thomas Mower’s argument, the government’s use of the specific items method does not require the government to prove any additional elements beyond those laid out in Anderson, 319 F.3d at 1219. Rather, the specific items method merely states the obvious with regard to the government’s burden to show a “substantial tax liability” under 26 U.S.C. § 7201: the government must produce evidence of a specific item of reportable income that the defendants did not — but should have — included on their income tax returns. The government has done so in the instant case, and the evidence was sufficient to support Thomas Mower’s convictions. B. Leslie Mower 1. Conspiracy There was sufficient evidence for a reasonable jury to find Leslie Mower guilty beyond a reasonable doubt of conspiracy to defraud the United States. The elements of conspiracy under 18 U.S.C. § 371 are “that (1) the defendant entered into an agreement; (2) the agreement involved a violation of the law; (3) one of the members of the conspiracy committed an overt act; (4) the overt act was in furtherance of the conspiracy’s object; and (5) the defendant wilfully entered the conspiracy.” United States v. Weidner, 437 F.3d 1023, 1033 (10th Cir.2006). “Secrecy and concealment are often necessary to a successful conspiracy, and, as a result, direct evidence of the crime is frequently difficult to obtain.” Id. Consequently, “conspiracy convictions may be based on circumstantial evidence, and the jury may infer conspiracy from the defendants’ conduct and other circumstantial evidence indicating coordination and concert of action.” Id. (citation and internal quotation marks omitted). The evidence was sufficient to show that Leslie Mower entered into an agreement to conceal approximately $3.2 million in foreign and domestic commission income. “ ‘The core of a conspiracy is an agreement to commit an unlawful act.’ ” Id. (quoting United States v. Morehead, 959 F.2d 1489, 1500 (10th Cir.1992)). “The existence of the agreement to violate the law may be inferred from a ‘unity of purpose or common design and understanding’ among conspirators to accomplish the objects of the conspiracy.” Id. (quoting United States v. Kendall, 766 F.2d 1426, 1431 (10th Cir.1985)). Leslie Mower was the Chief Financial Officer of Neways US. She was aware of the foreign commission checks and knew what they were, and, when the commission checks did not arrive on time, she would call John Hunter to inquire. In her interview with Agent Elder, she told him that she directed the financial operations of Neways U.S. and that anything financial at Neways U.S. would have to go through her. She was with her husband in Australia when they asked John Hunter to sign several of the commission checks over to cash. She often picked up the domestic commission checks from Neways US, and her endorsement appears on several of the domestic commission checks. Several commission checks were deposited into her personal savings account. She never disclosed these payments to anyone at Neways US, including Annette Jenkins and Karin Lane when she asked them to prepare the Mowers’ individual income tax returns. She was aware of the purchase of Hobble Creek and told John Hunter that she wanted to build a new house there. In addition, Allen Davis continually kept her apprised of the IRS investigation, including the false loan document that her husband presented to the IRS. Finally, despite all of this, Leslie Mower ultimately signed the amended corporate tax returns that Neways U.S. filed to mislead the IRS after the investigation began. The totality of this evidence was sufficient to prove beyond a reasonable doubt that Leslie Mower entered into an agreement with her husband to defraud the United States. It was also sufficient to show beyond a reasonable doubt that she entered into the agreement willfully. See Weidner, 437 F.3d at 1033. In addition, even though the government only had to prove that one of the members of the conspiracy committed an overt act in furtherance of the conspiracy, see Id., the evidence contained several examples of overt acts committed by Leslie Mower herself. The evidence was sufficient to convict Leslie Mower of conspiracy to defraud the United States. 2. Tax evasion Leslie Mower’s challenge to the sufficiency of the evidence also fails with regard to the six counts of tax evasion. “In order to prove a defendant guilty of tax evasion, the government must show (1) a substantial tax liability, (2) willfulness, and (3) an affirmative act constituting evasion or attempted evasion.” Anderson, 319 F.3d at 1219. For the same reasons as her husband, Leslie Mower had a “substantial tax liability” in 1992, 1993, and 1997. In 1994, 1995, and 1996, there was evidence of unreported income from the foreign commission checks, and for those years, the government also produced evidence of unreported domestic commission income. The government’s evidence of unreported income in 1994, 1995, and 1996 included: foreign commission checks used to purchase Hobble Creek in 1994; domestic and foreign commission checks deposited in Leslie Mower’s savings account in 1994 and 1995; domestic commission checks deposited in the Mowers’ checking account in 1994, 1995, and 1996; domestic and foreign commission checks deposited in the Mower Properties account in 1994, 1995, and 1996; domestic and foreign commission cheeks deposited in the Rezults account in 1994, 1995, and 1996; foreign commission checks drawn on the National Australia Bank in 1994 and 1995; and domestic and foreign commission checks of “unknown disposition” in 1994 and 1996. As explained previously, the evidence was sufficient for a reasonable jury to conclude beyond a reasonable doubt that this was personal income to the Mowers. In addition, the evidence previously cited as supporting Leslie Mower’s conviction for conspiracy to defraud the United States was also sufficient to show the final two elements for all six counts of tax evasion: “(2) willfulness, and (3) an affirmative act constituting evasion or attempted evasion.” Anderson, 319 F.3d at 1219. The government presented sufficient evidence for a reasonable jury to convict Leslie Mower of tax evasion for the years 1992 through 1997. C. James Thompson 1. Conspiracy There was also sufficient evidence to convict James Thompson of conspiracy to defraud the United States, in violation of 18 U.S.C. § 371. The elements of conspiracy are “that (1) the defendant entered into an agreement; (2) the agreement involved a violation of the law; (3) one of the members of the conspiracy committed an overt act; (4) the overt act was in furtherance of the conspiracy’s object; and (5) the defendant wilfully entered the conspiracy.” Weidner, 437 F.3d at 1033. James Thompson was aware that there was no documentation to support treating the monies used to purchase Hobble Creek as a loan, and further, that Neways Australia had not accounted for the monies as a loan. Yet, he decided to create a false, backdated loan document for the transaction. Then, during Agent Elder’s interview, James Thompson brought the false loan document to Thomas Mower, who presented it to Agent Elder. Neither James Thompson nor Thomas Mower informed Agent Elder that the document was backdated. In addition, James Thompson left two messages on Agent Elder’s answering machine, in which he tried to convince Agent Elder that they had given him all of the information that they had concerning the alleged Hobble Creek loan. The evidence was sufficient for a reasonable jury to find James Thompson guilty of conspiracy to defraud the United States. His creation of the false, backdated loan document, which Thomas Mower ultimately signed, and their joint presentation of that document to Agent Elder, showed “a unity of purpose or common design and understanding” between James Thompson and Thomas Mower, from which a reasonable jury could infer an agreement to commit an unlawful act. Weidner, 437 F.3d at 1033 (citations and internal quotation marks omitted). In addition, this series of events contained several overt acts in furtherance of the conspiracy, as well as evidence of willfulness. The evidence was sufficient to support James Thompson’s conviction for conspiracy. 2. Obstruction The evidence was also sufficient for a reasonable jury to convict James Thompson of corruptly endeavoring to interfere with the administration of internal revenue laws. “In order to establish a violation of 26 U.S.C. § 7212(a), the government must prove that a defendant ‘corruptly’ endeavored to obstruct and impede the due administration of the internal revenue laws.” United States v. Winchell, 129 F.3d 1093, 1098 (10th Cir.1997). In this context, “to act corruptly means to act with the intent to secure an unlawful benefit either for oneself or for another.” Id. James Thompson was aware of the pending IRS investigation. He responded by creating a false, back-dated loan document, which Thomas Mower signed and which they presented to Agent Elder without informing him that it was back-dated. He knew, before creating the false loan document, that no documentation supported treating the Hobble Creek monies as a loan, and that Neways Australia had not accounted for the monies as a loan. In addition, after presenting the false loan do