The ad valorem fees prescribed in sections three and three-a of this article shall be reduced in the amount of ad valorem fees paid on the original vehicle upon the transfer of registration by an owner from the original vehicle to another vehicle of the same class. The reduction in the amount of ad valorem fees paid on the original vehicle shall be prorated monthly up to the amount of ad valorem fees owed on the vehicle to which registration is being transferred. Any remainder of ad valorem fees paid on the original vehicle shall be reviewed by the interstate appeals board, created in section seven of this article.