Proposed amendments, supplementations, modifications, or repeals of or to this title shall be heard at a public hearing by the city council within 90 days of the time that the petition was filed. No request for a zone boundary or zone classification amendment to this title shall be reconsidered within the 12-month period immediately following a previous denial of such request, except where, in the opinion of the city council, such a hearing is warranted by new evidence or a substantial change of circumstances.