The mortgage shall be an insured mortgage from the date of the issuance of a Mortgage Insurance Certificate, from the date of the endorsement of the credit instrument, or from the date of HUD's electronic acknowledgement to the mortgagee that the mortgage is insured, as applicable. The Commissioner and the mortgagee are thereafter bound by the regulations in this subpart with the same force and to the same extent as if a separate contract had been executed relating to the insured mortgage, including the provisions of the regulations in this subpart and of the Act.