(a) In each subsequent sale of gasoline on which the tax has been paid, the tax imposed by this subchapter shall be collected from the purchaser so that the tax is paid ultimately by the person who uses the gasoline. Gasoline is considered to be used when it is delivered into a fuel supply tank.
(b) The tax imposed by this subchapter must be stated separately from the sales price of gasoline and identified as gasoline tax on the invoice or receipt issued to a purchaser. Backup gasoline tax may be identified as gasoline tax. The tax must be separately stated and identified in the same manner on a shipping document, if the shipping document includes the sales price of the gasoline.

(c) Except as provided by Subsection (d), the sales price of gasoline stated on an invoice, receipt, or shipping document is presumed to be exclusive of the tax imposed by this subchapter. The seller or purchaser may overcome the presumption by using the seller’s records to show that the tax imposed by this subchapter was included in the sales price.
(d) Subsection (b) does not apply to a sale of gasoline by a licensed dealer to a person who delivers the gasoline at the dealer’s place of business into a fuel supply tank or into a container having a capacity of not more than 10 gallons.