The Council may determine the annual salary of Councilpersons and Mayor by ordinance, but no ordinance increasing or decreasing such salary shall become effective until the date of commencement of the terms of Councilpersons elected at the next regular election, provided that such election follows the adoption of such ordinance by at least six months. For each absence from regular meetings of the Council, unless authorized by an affirmative vote of a majority of the members thereof, there shall be deducted a sum equal to two percent of such annual salary. Councilpersons shall receive their actual and necessary expenses incurred in the performance of their duties of office. The Mayor shall receive such additional compensation to that received as Councilperson as the Council shall by ordinance determine, upon the affirmative vote of three- fourths of the members thereof, exclusive of his/her own.