Upon request by the mortgagor and mortgagee the Commissioner may terminate the insurance contract on any mortgage under this part covering a 1-to-4 family residence. The mortgagee shall cancel the insurance endorsement on the mortgage insurance certificate or note upon receipt of notice from the Commissioner that the contract of insurance is terminated. Notwithstanding any provision in a mortgage instrument, there shall be no voluntary termination charge due the Commissioner on account of the voluntary termination of any mortgage insurance contract where the request for termination is received by the Commissioner on or after May 1, 1972.