(a) Payment of periodic insurance premiums or charges. Except with respect to mortgages for which a one-time mortgage insurance premium is paid pursuant to § 203.280, the mortgage may provide for monthly payments by the mortgagor to the mortgagee of an amount equal to one-twelfth of the annual mortgage insurance premium payable by the mortgagee to the Commissioner. Such payments continue only so long as the contract of insurance shall remain in effect or for such shorter period as mortgage insurance premiums are payable by the mortgagee to the Commissioner.

(b) Prepayment privilege. The mortgage shall contain a provision permitting the mortgagor to prepay the mortgage in whole or in part at any time and in any amount. The mortgage shall not provide for the payment of any charge on account of such prepayment.