The City Council may, on its own motion, amend, supplement, change, modify, or repeal the district boundaries or ordinance text. Prior to such action, a report and recommendation from the Planning and Zoning Board must be received by the City Council and publication of a public hearing notice must appear at least twice in a newspaper printed or published in the City of St. John. However, if no newspaper be printed or published in the City, then said notice shall be published in some daily, tri-weekly, semi-weekly, or weekly newspaper, of general circulation in the City. Publication shall commence not more than thirty (30) nor less than fifteen (15) days before the hearing date. Every affidavit to proof of publication shall state that said publication and the newspaper in which notice was printed has met the requirements of the foregoing provisions and those of Chapter 493, RSMo., 1969, governing legal publications, notice and advertisement. Public notice for such amendments shall not require the posting of any signs. It shall not be necessary to publish notice or hold public hearings on amendments to this Chapter pertaining to procedural matters and to the duties and powers of officials, officers, boards, commissions and bureaus in carrying out the regulations of this Chapter.