S.D. Codified Laws § 32-5-8.4
Any owner of a motor vehicle licensed for fifty thousand pounds or more in accordance with the provisions of § 32-5-6.3 or 32-5-8, who operates upon the public highway or allows to be operated thereon, any motor vehicle the weight of which, together with its load, exceeds the gross weight for which the vehicle is licensed, shall be deemed to have specified such greater weight and to have agreed to pay the appropriate fee and shall pay the amount of the appropriate fee which exceeds the amount of the fee actually paid, for the remainder of the registration period. Such additional amount is compensation and not a penalty or fine, and the payment thereof does not constitute a defense or bar to conviction for such, or any other violation of this chapter.
SDCL 32-5-8.4