The regulations, restrictions, and boundaries may, from time to time, be amended, supplemented, changed, modified, or repealed, provided that at least seven days’ notice of the time and place of such hearing shall be published in a paper of general circulation in the City. In no case shall the notice be published more than 20 days prior to the hearing. Notwithstanding Section 414.2 of the Code of Iowa, as a part of an ordinance changing land from one zoning district to another zoning district or an ordinance approving a site development plan, a Council may impose conditions on a property owner which are in addition to existing regulations if the additional conditions have been agreed to in writing by the property owner before the public hearing required under this section or any adjournment of the hearing. The conditions must be reasonable and imposed to satisfy public needs which are directly caused by the requested change. In the case, however, of a written protest against a change or repeal which is filed with the City Clerk and signed by the owners of 20 percent or more of the area of the lots included in the proposed change or repeal, or by the owners of 20 percent or more of the property which is located within 200 feet of the exterior boundaries of the property for which the change or repeal is proposed, the change or repeal shall not become effective except by the favorable vote of at least three-fourths of all the members of the Council. The protest, if filed, must be filed before or at the public hearing. Proposed amendments not recommended by the Planning and Zoning Commission shall become effective only upon a favorable vote of three-fourths of the members of the City Council. All zoning amendment application forms shall be approved by resolution of the City Council.