If the commission fails to pass an ordinance proposed by the initiative petition, or pass it in a form different from that set forth in the petition therefor, the committee of the petitioners hereinafter provided for may, by an additional petition signed by voters, in no case less than fifty in number and equal to at least five percent of the number who voted at the last regular municipal election, who did not sign the petition by which the ordinance was originally proposed to the commission, require that it be submitted to a vote of the voters either in its original form or with any change or amendment which was presented in writing during the consideration thereof by the commission or its committee. If the committee of petitioners require the submission of a proposed ordinance to a vote of the voters they shall certify that fact to the city secretary and file in the city secretary’s office a certified copy of the measure, in the form in which it is to be submitted, together with the additional petition as provided in this section, within ten days after final action on such ordinance by the commission.