State chartered credit unions may charge such rates of interest and other finance charges as are authorized for other financial institutions pursuant to the Alabama Consumer Credit Act or other applicable law and may charge a late charge in an amount authorized by the Alabama Consumer Credit Act, provided that such late charge may only be assessed on simple interest loans and simple interest open-end credit plans. As used herein, "simple interest" means charging an interest rate on the unpaid balances of the amount outstanding from time to time for the actual time such balance is outstanding.
Ala. Code § 5-17-18 (1975)