After conducting the hearing on the tentative 9-1-1 service plan under this act, the board of commissioners of the affected county may adopt by resolution the tentative 9-1-1 service plan making it the final 9-1-1 service plan. Upon adoption of the resolution, the county, on behalf of public agencies located within the 9-1-1 service district, shall apply in writing to the service supplier or suppliers designated to provide 9-1-1 service within the 9-1-1 service district under the final 9-1-1 service plan.