Except as provided in sections 9-164b to 9-164f, inclusive, the term of each elected municipal official shall begin within seventy days after the municipal election at which such official is elected, on the day within such period prescribed by special act or charter provision, or, in the absence of such special act or charter provision, on the day within such period as is prescribed by action of the legislative body of such municipality, provided (1) in each municipality which holds its municipal election on the first Monday of May in the odd-numbered years, in the absence of such special act or charter provision, or action of the legislative body, such terms shall begin on the first day of July following the municipal election at which such official is elected, and (2) in each municipality which holds its municipal election on the Tuesday after the first Monday of November in the odd-numbered years, with the exception of the term of the town clerk, in the absence of such special act, or charter provision, or action of the legislative body, such term shall begin on the second Tuesday next following the day of the municipal election at which such official is elected, and (3) in each municipality which holds its municipal election on the Tuesday after the first Monday in November in the odd-numbered years, the term of the town clerk shall be two years from the first Monday of January next succeeding his election, unless otherwise provided by charter or special act. Whenever the beginning date of the terms of elected municipal officials is so determined or changed, within the limits hereinabove specified, the authority providing therefor may provide for the conforming diminution or extension of terms of incumbents.