(a) Each licensed liquefied gas special fuels supplier or interstate user shall compute, report, and pay the tax on all liquefied gas special fuels used in each vehicle owned or operated by him or her in this state on which the tax levied by this subchapter has not been paid by ascertaining the total highway miles driven in this state and dividing this total by the applicable mileage factor, as set forth below, to compute the quantity of special fuel used upon which the tax levied in § 26-56-301 is applicable.

(b)

(1) For the purpose of this section, all automobiles with a capacity of fewer than eight (8) passengers shall be deemed to be Class A vehicles.

(2) All truck-type vehicles with a factory rating and gross loaded weight of less than twenty-two thousand five hundred pounds (22,500 lbs.) shall be deemed to be Class B vehicles.

(3) All vehicles with a factory rating in excess of twenty-two thousand five hundred pounds (22,500 lbs.) or whose total gross loaded weight exceeds twenty-two thousand five hundred pounds (22,500 lbs.) shall be deemed to be Class C vehicles.

(c) The mileage factor per gallon of liquefied gas special fuels for:

(1) Class A vehicles shall be twelve (12) miles;

(2) Class B vehicles shall be eight (8) miles; and

(3) Class C vehicles shall be four (4) miles.

(d) When calculating the number of gallons of liquefied gas special fuels on which the gallonage tax levied by § 26-56-301 is due, the suppliers and users shall be allowed a credit equal to the amount of the tax paid on each gallon of liquefied gas special fuels purchased or received in this state when each credit is supported by a copy of the purchase invoice showing the amount of tax paid, signed by the supplier or dealer from which the liquefied gas special fuels was purchased or delivered.

(e) The due date of the interstate user reports shall be the twenty-fifth day following each calendar quarter.