Within thirty days after the filing of the original certificate, the committee shall file the completed petition in the office of the City Administrator. The City Administrator shall examine the petition within the next five days, and if he finds it irregular in any way, or finds that the number of signers is less than a number of voters at least equal to twenty-five per cent of the total number of voters registered on the date of the last preceding regular municipal election, he shall so notify one or more members of the committee. The committee shall then be given ten days in which to file additional signature papers and to correct the petition in all other respects, but they may not change the statement of the grounds upon which the recall is sought. If at the end of that time the City Administrator finds the petition still insufficient or irregular, he shall notify all the members of the committee to that effect and shall file the petition in his office. No further action shall be taken thereon.