The terms of all Class IV members first appointed pursuant to this chapter shall be so determined that, to the greatest practicable extent, the expiration of such terms shall be evenly distributed over the first four years after their appointment as determined by resolution of the governing body; provided, however, that no term of any member shall exceed four years, and further provided that nothing herein shall affect the term of any present member of the Planning Board, all of whom shall continue in office until the completion of the term for which they were appointed. Thereafter, all Class IV members shall be appointed for terms of four years, except as otherwise herein provided. All terms shall run from January 1 of the year in which the appointment was made.