Town officers who are to be elected by ballot as provided in N.H. Rev. Stat. § 669:15 and all other officers that a town has voted at some previous meeting to elect by ballot shall be elected by means of the partisan or non-partisan official ballot systems if such an official ballot system shall be in effect in a town. In towns where no such official ballot system is in effect, town officers who are to be elected by ballot as provided in N.H. Rev. Stat. § 669:15 and such other officers as the town votes to elect by ballot shall be elected by unofficial ballot at the town business meeting pursuant to N.H. Rev. Stat. § 669:54-669:60.