(1) There is deducted 2% from the gross amount of motor fuel taxable under this part to allow for all evaporation, loss in handling, and expenses of collection. All distributors shall report the gross amount of taxable motor fuel which is produced, received, refined, or sold in this state from which this deduction shall be made.
(2) At the time of submitting the report and payment of the tax, the producers and refiners shall further submit evidence to the satisfaction of the commission that from the amount of the 2% deduction made by them, one half of the deduction has been paid to the registered retail dealers on quantities sold to them during the period covered by the report.