(a) In any fiscal year in which the total amount available for allocation of HTF funds is less than $1 billion, the grantee must use 100 percent of its HTF grant for the benefit of extremely low-income families or families with incomes at or below the poverty line (whichever is greater). In any fiscal year in which the total amount available for allocation of HTF funds is greater than $1 billion, the grantee must use at least 75 percent of its grant for the benefit of extremely low-income families or families with incomes at or below the poverty line.

(b) Any grant funds not used in accordance with paragraph (a) of this section must be used for the benefit of very-low income families.