In addition to the requirements set forth in Sections 81-25 (General Provisions Relating to Height and Setback of Buildings) and 81-40 (MANDATORY DISTRICT PLAN ELEMENTS), the provisions of this Section shall apply to a zoning lot having 50 percent or more of its lot area within the Penn Center Subdistrict. For the purposes of this Section, all such zoning lots shall be deemed to be entirely within the Subdistrict. If any of the provisions of Sections 81-25, 81-40 and 81-53 are in conflict, the regulations of this Section shall govern.