(a) This section applies only for purposes of disclosure.
(b) The finance charge on a credit transaction is computed on the unpaid balance from the effective date of the transaction provided by the credit document until the payment date of the final installment, notwithstanding that the total of payments is required to be repaid in installments.
(c) The finance charge on a credit transaction that includes an adjustable rate provision is computed on the amount financed using the initial contract rate.