(a) Any proposal for the amendment of this Zoning Ordinance not originating from petition of the Planning Commission shall be referred to the Commission for consideration and report before any final action is taken by Council.
(b) The Commission shall study a proposed amendment in relation to public necessity, convenience, general welfare and good zoning practice and within forty-five days after Council referral, shall recommend the approval or denial of the proposed amendment or approval of some modification thereof, and submit such recommendation to Council. Failure of the Planning Commission to report within the required forty-five days shall be construed as approval of the proposed amendment or change.