S.C. Code Ann. § 37-2-205

With respect to a consumer credit sale, refinancing, or consolidation, the seller may by agreement with the buyer refinance the unpaid balance and may contract for and receive a credit service charge based on the amount financed resulting from the refinancing at a rate not exceeding that permitted by the provisions on credit service charge for consumer credit sales (Section 37-2-201). For the purpose of determining the credit service charge permitted, the amount financed resulting from the refinancing comprises the following: (1) If the transaction was not precomputed, the total of the unpaid balance and accrued charges on the date of refinancing, or, if the transaction was precomputed, the amount which the buyer would have been required to pay upon prepayment pursuant to the provisions on rebate upon prepayment (Section 37-2-210) on the date of refinancing, except that for the purpose of computing this amount, no minimum credit service charge [Section 37-2-201(6)] shall be allowed; and (2) Appropriate additional charges (Section 37-2-202), payment of which is deferred.