The State Department of Social Services shall establish and maintain a plan whereby costs of county administered social services programs will be effectively controlled within the amount annually appropriated for these services. Each county shall utilize least cost services, provided that the quality of services is maintained. Allocations shall be made to each county and shall be limited by, and determined based upon, an allocation plan developed by the State Department of Social Services and approved by the Department of Finance. In administering the plan, the State Department of Social Services shall not allocate funds to cover county cost overruns which result from county failure to meet requirements of the plan.