The Administration shall allow a credit for any excise tax paid by a consumer or owner for a vehicle returned under Regulation .02A and C of this chapter towards the excise tax imposed for a replacement vehicle. If the excise tax on the replacement vehicle exceeds that paid on the returned vehicle, the consumer or owner shall pay the difference to the dealer. If the excise tax on the replacement vehicle is less than that paid on the returned vehicle, the Administration shall refund the difference to the consumer or owner.