Should the council decide to submit the proposal to the electors, it shall be submitted at the next election held in the city for any other purpose, or, if the discretion of the council, at a special election called for that specific purpose. In the case of an initiatory petition, if no election is to be held in the city for any other purpose within one hundred fifty days from the time the petition is presented to the council and the council does not enact the ordinance[,] then the council shall call for a special election within ninety days from such date. The results of all elections, held under the provisions of this section[,] shall be determined by a majority vote of the electors voting thereon, except in cases where otherwise required by law or the terms of this charter.