(a) General rule.--Every motor carrier subject to the tax imposed under this chapter shall be entitled to a credit on the tax, equivalent to the rate per gallon of the Pennsylvania tax which is currently in effect, on all gasoline or other motor fuel purchased by the carrier within this Commonwealth for use in its operation either within or without this Commonwealth and upon which gasoline or other motor fuel the tax imposed by the laws of this Commonwealth has been paid by such carrier. Evidence of the payment of the tax in such form as may be required by, or is satisfactory to, the department shall be furnished by each carrier claiming the credit. When the amount of the credit to which any motor carrier is entitled for any quarter exceeds the amount of the tax for which the carrier is liable for the same quarter, such excess shall, upon application and under regulations of the department, be allowed as a credit on the tax for which the carrier would be otherwise liable for any of the eight succeeding quarters; or, upon application to the department within the time that records are required to be maintained from the end of any quarter, duly verified and presented, in accordance with regulations promulgated by the department and supported by such evidence as may be satisfactory to the department, such excess shall be refunded if it shall appear that the applicant has paid to another state under a lawful requirement of such state a tax, similar in effect to the tax provided in this chapter, on the use or consumption in that state of gasoline or other motor fuel purchased in this Commonwealth.

(b) Refund procedure.--If the department shall refuse to allow a refund in the amount claimed by the applicant, the applicant may within 30 days of the mailing date of the notice of such refusal request a formal hearing on the application for a refund. The hearing shall be held after written notice to the applicant of not less than 20 days. Whenever any refund is ordered, it shall be paid out of the Motor License Fund. As much of the moneys received as payment of the tax, interest and penalties under this chapter as shall be necessary for the payment of the refunds provided for in this chapter is hereby appropriated for the payment of such refunds. No tax, interest, penalty or fee received or derived from any other tax imposed by the laws of this Commonwealth shall be used to pay any refund or credit due and payable under the provisions of this chapter.