The term of office of each member of the Commission is four years. Appointments shall be made on or before June 15 of the year in which any appointment is to be made, and terms of office shall begin as of that date and if any appointment is not made as provided in this section a vacancy exists which shall be filled as provided in this article for the filling of vacancies on the Commission. The members of the Commission in office immediately prior to July 1, 1975 shall remain in office under the provision of this article for the remainder of the terms for which they were appointed. Members may continue to serve until their successors are appointed and have qualified. In Montgomery County a person may not be appointed for 3 consecutive, full terms. Those members who have served 2 consecutive terms may complete their current terms.