Sec. 561.9. Refunds and credits of prepaid tax—general

(a) Pursuant to section 561.10 of this Part, a refund or credit of prepaid tax will be allowed under certain circumstances to the party which has paid or had passed through to it such prepaid tax.

(b) A refund of prepaid tax will be allowed only to the extent that the prepaid tax which has been paid by or passed through to the claimant with respect to particular motor fuel exceeds the liability for tax incurred by the claimant on the retail sale or use of such motor fuel.

(c) A claim for a credit of prepaid tax may not exceed the amount of such tax actually paid by or passed through to the claimant with respect to particular motor fuel.