No small loan lender shall enter into any contract of loan under this chapter of one thousand dollars ($1,000) or less, excluding charges, under which the borrower agrees to make any scheduled repayment of cash advance or principal more than twenty-five (25) months from the date of making the contract, nor, any contract of small loan exceeding one thousand dollars ($1,000), but not exceeding five thousand dollars ($5,000), excluding charges, under which the borrower agrees to make any scheduled repayment of cash advance or principal more than sixty (60) months from the date of making the contract. Every contract of small loan shall provide for repayment of the loan in substantially equal installments at approximately equal periodical intervals of time.