After the 1980 general district election and the seating of the newly elected directors, the board of directors of the district may increase the number of directors pursuant to Section 34708. If the number of directors is increased, the term of office of new directors shall be determined so as to be consistent with the provisions of this chapter and the requirements of Section 34708. Expansion of the board of directors shall not affect the manner of electing directors at large as provided in this chapter.