Whenever a housing sponsor of a rental or cooperative housing development accumulates an earned surplus greater than such operating and replacement reserves as the agency may require, that surplus shall be used to reduce rents within the housing development to a level at which no person or family of low or moderate income occupying the housing development pays more than the affordable rent. Whenever a housing sponsor of a rental or cooperative housing development accumulates an earned surplus greater than such operating and replacement reserves as the agency may require and no person or family of low or moderate income occupying the housing development pays more than the
affordable rent, then such surplus shall be transferred to the agency for use in lowering the rents for persons and families of low or moderate income in other housing developments to a level no greater than the affordable rents.