Timothy J. Coley, Comment, Disputed Deductions: Delfino and the Fourth Circuit's Prudent Adoption of the Restrictive Approach to Tax Evasion Sentencing (United States v. Delfino, 510 F.3d 468.), 87 N.C. L. Rev. 234 (2008).  Here is part of the Conclusion:

Ultimately, the holding in United States v. Delfino illustrates that the Fourth Circuit, like numerous circuits before it, has realized that disallowing convicted tax evaders the subsequent benefit of unclaimed deductions is the most prudent practice. This restrictive approach to tax loss calculation is fundamentally consistent with the policies underlying the prosecution of tax offenses and the Guidelines, whereas the permissive approach, which allows for the retroactive recognition of deductions, is erroneous, inequitable, and untenable. Furthermore, the federal courts have by and large acknowledged the superiority of the restrictive approach, as there has been a consistent trend toward its adoption and a corresponding rejection of the permissive approach in recent years. This trend will likely continue as undecided federal circuits hear future cases and recognize the appropriateness of the restrictive approach. Nonetheless, even though the courts appear to be converging toward the adoption of the restrictive approach, the Commission's objective behind the ‘93 Amendments of eliminating sentencing anomalies has  never been fully realized.  Yet, this goal can finally be achieved through the enactment of a Revised Amendment to § 2T1.1 that explicitly rejects the use of unclaimed deductions for sentencing purposes. Such a Revised Amendment would not only produce doctrinal uniformity among the federal courts, but would also provide an approach that is fundamentally consistent with the policies of administrability, retribution, deterrence, and stricter sentencing that underlie the United States Sentencing Guidelines.