S.C. Code Ann. § 37-2-201
(2) The credit service charge, calculated according to the actuarial method, may not exceed the greater of either of the following:
(3) This section does not limit or restrict the manner of contracting for the credit service charge, whether by way of add-on, discount, or otherwise, so long as the rate of the credit service charge does not exceed that permitted by this section. If the sale is precomputed,
(5) Subject to classifications and differentiations the seller may reasonably establish, he may make the same credit service charge on all amounts financed within a specified range. A credit service charge so made does not violate subsection (2) if