A zoning lot containing a development, or portion thereof, on a waterfront zoning lot, may be located within the volume above the upper limiting plane of the Battery Park Underpass/South Street, when such volume is eliminated, discontinued and closed. That portion of the zoning lot that lies above the Battery Park Underpass/South Street shall not be considered lot area for the purpose of computing maximum floor area; however, such portion shall be considered lot area for all other purposes of this Resolution.