For assessments issued on or after November 19, 2003, an auditor may grant a credit for overpayments. If the taxpayer believes that tax has been overpaid during the period under audit and the auditor will not grant a credit, the taxpayer must file a petition for refund within six months of the mailing date of the notice of assessment for the audit period. If a petition is not filed within this timeframe, the taxpayer forfeits the right to claim a refund or credit for the period that was audited. (Pennsylvania Sales Tax Bulletin 2004-02, May 3, 2004.)