(1) (a) The Department of Revenue may grant a refund, in whole or in part, upon determination that a tax, water or sewer rent, license fee or other charge, interest or penalty, or any part thereof, has been paid under mistake of law or fact, or under an invalid law.^[239]

(b) Every petition for refund of moneys collected by the Department on or before December 31, 1979, for or on behalf of the City of Philadelphia, including but not limited to any tax, water or sewer rent, license fee or other charge, and interest and penalties thereon, shall be filed with the Department within 6 years from the date of payment of the City.^[240]

(c) Every petition for refund of moneys collected by the Department on or before December 31, 1979, for or on behalf of the School District of Philadelphia, including but not limited to any tax, license fee or other charge, and interest and penalties thereon, shall be filed with the Department within 2 years from the date of payment thereof.^[241]

(d) Every petition for refund of moneys collected by the Department on or after January 1, 1980, for or on behalf of the City or the School District of Philadelphia, including but not limited to any tax, water or sewer rent, license fee or other charge, and interest and penalties thereon, shall be filed with the Department within 3 years from the date of payment to the City or the School District of Philadelphia or the due date, whichever is later.^[242]

(2) Every petition for refund shall state the reasons upon which the petitioner relies and shall include a certification by the petitioner that the facts set forth therein are true.

(3) The Department shall, within a reasonable time, consider each petition for refund and notify the petitioner in writing of its decision thereon.^[243]

(4) A decision of the Department granting a refund in whole or in part shall become final only after it has been reviewed, approved, and/or modified by the Tax Review Board; provided that such review and approval is not required where the Department grants a refund because of an overpayment resulting from duplication of payments or mathematical error in computation or other mechanical error such as a typographical error, or when the Department grants a refund which is less than one thousand ($1,000) dollars.^[244]

(5) When the Department grants a refund in a case which does not require the review and approval of the Tax Review Board, then upon certification thereof to the Director of Finance, the City Controller and the City Treasurer, the Treasurer shall make payment of such refund to the petitioner or, where the petitioner is indebted to the City or the School District of Philadelphia, the account of such petitioner may be credited with the amount of such refund.^[245]

(6) Before the Tax Review Board disapproves or modifies any refund granted by the Department, it shall afford the petitioner and the Department a hearing before the Board.^[246]

(7) Any decision of the Department denying a refund in whole or in part may be appealed to the Tax Review Board by the petitioner within 90 days after the mailing of notice of such decision to the petitioner by the Department.^[247]

(8) When the Tax Review Board grants a refund in whole or in part and no appeal is taken from such decision within 30 days after notice of such decision is given, then upon certification thereof by the Tax Review Board to the Director of Finance, the City Controller and the City Treasurer, the Treasurer shall make payment of such refund to the petitioner or, where the petitioner is indebted to the City or the School District of Philadelphia, the account of such petitioner may be credited with the amount of such refund.^[248]

(9) Any refund made pursuant to the provisions of this Section shall be charged against the account to which the payment was originally credited unless otherwise determined by the Director of Finance in accordance with sound accounting practice, and no other councilmanic authorization for payment shall be required.