The director of developmental disabilities shall adopt rules in accordance with Chapter 119. of the Revised Code governing the authorization and payment of home and community-based services and medicaid case management services. The rules shall provide for private providers of the services to receive one hundred per cent of the medicaid allowable payment amount and for government providers of the services to receive the federal share of the medicaid allowable payment, less the amount withheld as a fee under section 5123.0412 of the Revised Code. The rules shall establish the process by which county boards of developmental disabilities shall certify and provide the nonfederal share of medicaid expenditures that the county board is required by sections 5126.059 and 5126.0510 of the Revised Code to pay. The process shall require a county board to certify that the county board has funding available at one time for two months costs for those expenditures. The process may permit a county board to certify that the county board has funding available at one time for more than two months costs for those expenditures.