The total interest for payment according to schedule may be added to the principal of the loan, but interest shall not be discounted or deducted from the principal of the loan, or paid or received at the time the loan is made, and shall not be compounded. Loan contracts may be calculated and repaid as follows:
(1) A loan contract may provide for repayment in consecutive monthly installments, but the first installment may be payable at any time within forty-five days from the date of the loan and no installment shall be substantially greater than any other installment. Interest for any fractional portion of a month may be computed for each elapsed day at one-thirtieth of the monthly rate contracted for.
(2) A loan contract may provide for repayment as the parties may agree; however, any such loan contract shall provide for the payment of simple interest on such loans at rates not to exceed those authorized by sections 408.100 and 408.200.