The Mayor or other presiding officer of the Council shall set a date for a public hearing on each ordinance or resolution establishing, amending, revising, changing or repealing zoning classifications, districts, uses or regulations, which hearing shall be after the thirty (30) day period provided in Section 4.12 within which the Planning Commission is required to return its written recommendation to the Clerk of Council. The Clerk of Council shall cause a notice of such public hearing to be published one (1) time in a newspaper determined by the Council to be of circulation within the Municipality at least fifteen (15) days prior to the date of such public hearing, and when such amendment, revision, change, or repeal involves ten (10) or less parcels of land, as listed on the tax duplicate, written notice of the hearing shall be mailed by the Clerk of Council by certified mail with return receipt, at least fifteen (15) days before the date of public hearing to the owners of property within and contiguous to and directly across the street from such parcel or parcels to the addresses of such owners appearing on the County Auditor's current tax list or the Treasurer's mailing list and to such other lists as may be required by the Council. The failure of delivery of such notice shall not invalidate any such ordinance or resolution.