Those counties presently electing the supervisor shall continue to do so and he shall serve as chairman of the board of commissioners. Those counties presently hiring or appointing the supervisor or administrator shall continue to do so. Method of election and terms of office of either two years or four years for the supervisor and board of commissioners shall be as the General Assembly shall provide when a form of government is selected for the county concerned. In the event terms for commission members are established for four years, terms of office shall be staggered so that not more than one-half of the board of commissioners shall be elected at any single general election except the initial election at which time one-half of the membership shall be elected for two years only.

Terms shall commence on the Monday following their election. Vacancies shall be filled in the same manner for the unexpired portion of the term only. Provided, that any vacancy having less than one year of the term remaining shall be filled in the manner provided for boards, committees and commissions in § 4-9-1100.