An existing mortgage insured under the Act, or an existing mortgage held by the Secretary that is subject to a mortgage restructuring and rental assistance sufficiency plan under the Multifamily Assisted Housing Reform and Affordability Act, 42 U.S.C. 1437f note (MAHRA), may be refinanced pursuant to section 223(a)(7) of the Act and such terms and conditions as may be established by the Commissioner. The term of such refinancing in connection with the implementation of an approved restructuring plan under section 401, subpart C of this title, may be up to, but not more than, 30 years.