Notwithstanding the provisions of sections 207.010, 208.152, and 208.153, the department of social services shall administer payments for nursing home services authorized in sections 208.151, et seq., which govern medical assistance under Title XIX, Public Law 89-97, 1965 amendments to the Federal Social Security Act (42 U.S.C. § 301 et seq.), as amended, and shall administer vendor payments for the aged and direct adult services for the aged under Title XX, Public Law 93-647, 1974 amendments to the Federal Social Security Act (42 U.S.C. § 1397 et seq.), as amended. The department shall, pursuant to chapter 536, promulgate rules and regulations for the purpose of administering such payments, including rules to define the reasonable costs, manner, extent, quality, charges and fees or^* payments for nursing home services.