(3) This section does not limit or restrict the manner of calculating the finance charge, whether by way of add-on, discount, single annual percentage rate, or otherwise, so long as the rate of the finance charge does not exceed that permitted by this section.
If the loan is a precomputed consumer credit transaction:
(a) the finance charge may be calculated on the assumption that all scheduled payments will be made when due; and
(b) the effect of prepayment is governed by the provisions on rebate upon prepayment (Section
37-3-210 ).