A creditor may, by written agreement with the buyer, refinance the unpaid balance and may contract for and receive a finance charge based on the amount refinanced. Any rebate due to the buyer pursuant to the provisions of § 54-3A-9 if the buyer was prepaying in full on the date of the refinancing is excluded from the amount to be refinanced. No minimum finance charge, for the purpose of computing this rebate, is allowed to the creditor.
SDCL 54-3A-17