A sales and use tax audit performed on purchases made for the period of 1991 to 1994 disallowed any overpayments in its calculation, stating that the overpayment claims were not filed within the three-year statute. The taxpayer’s request for a reduction in the assessment was denied. However, the Supreme Court unanimously overturned both the Department and the lower court stating that “Once a taxpayer is audited it doesn’t have to seek a refund for overpayments during the audit period because it is the duty of the auditor to ensure that the proper amount of tax was collected, which necessarily requires that the audit take into account situations where the taxpayer overpaid tax or paid tax it did not have to during the audit period.” [McNeil-PPC, Inc. v. Commonwealth of Pennsylvania , J-53-2003, No. 99 MAP 2002, (Pa. Supreme Court, Middle District, October 22, 2003); McNeil-PPC, Inc. v. Commonwealth of Pennsylvania , No. 353 F.R. 1998, Commonwealth Court of Pennsylvania, June 28, 2000. Decision was overturned by Pennsylvania Supreme Court on October 22, 2003.]