In the establishment of the rate schedules for out-of-home care, the director shall consider and reflect in the rate schedule annually, in addition to any other factors he deems to be relevant, the availability of such homes in the community, cost of living, appropriateness of the facility, the cost of providing care under the required standards, activity programs required for the maintenance or restoration of function of aged and disabled persons and the cost of differentials of room, board and care required for persons of differing ages and needs.