Any loan contract subject to the provisions of this subchapter shall have an originally scheduled final installment date not later than 48 months, fifteen days from the date of the loan. Notwithstanding any other provisions of this subchapter the charges which may be collected on any loan made under this subchapter for the period beginning six months after the originally scheduled or as deferred final installment date of the loan and ending with date of payment of the loan in full shall not exceed 2 percent per month simple interest on the balances outstanding from time to time during said period.