In construing this act, port districts coterminous with a city or township shall follow the same procedure, as near as may be, substituting the local governing body and local officers where applicable for the board of supervisors and county officials, shall enjoy the same powers and be subject to the same conditions as set forth for county port districts, and port districts coterminous with 2 or more cities or townships shall in the same manner follow the same procedure, as near as may be, shall enjoy the same powers and be subject to the same conditions as set forth for port districts coterminous with 2 or more counties.