The term of office of all commissioners, except any ex officio member, shall be for two years from the date of their election and until their successors are qualified; provided, however, that of the first members of the commission, one-half shall serve for one year, and one-half shall serve for two years, with the determination of term of each such member to be made by lot at the time of election. The same selection procedure shall apply to the two handler members. Terms of office of each commissioner shall be limited to four consecutive terms, except that any member selected to serve a one-year term may serve one additional two-year term.