the production, preservation, and rehabilitation of rental housing, including housing under the programs identified in
section 4565(a)(2)(B) of this title and for operating costs, except that not less than 75 percent of such grant amounts shall be used for the benefit only of extremely low-income families or families with incomes at or below the poverty line (as such term is defined in
section 9902 of title 42, including any revision required by such section) applicable to a family of the size involved, and not more than 25 percent for the benefit only of very low-income families; and