(1) The amount of public assistance which any eligible person or family may receive shall be determined in accordance with the rules of the state department subject to the availability of funds for such assistance.
(2) Old age assistance, aid to the blind and aid to the permanently and totally disabled shall be granted to a person who is needy as defined by the department and who meets the nonfinancial requirements of title XVI of the social security act.
(3) The department may also increase or decrease the payment for groups of cases where the circumstances are specifically identified. The department shall be the single state agency for administration of public assistance programs or plans that receive federal funding.