Required spaces and berths. For all institutional, recreational, social, commercial, industrial, and utility/transportation uses, excepting a church, whose principal buildings have an aggregate floor area exceeding 6,000 square feet, at least one off-street loading space/berth shall be provided. Where there is an aggregate of 20,000 square feet or more, one off-street loading space/berth shall be provided for the initial 20,000 square feet, plus one additional space/berth shall be provided for each 60,000 square feet above 20,000 square feet. All off-street loading spaces and berths shall be provided and maintained so long as the use exists which the facilities were designed to serve. They may, however, be reduced in number after their provision by special exception in a manner similar to that provided in § 500-108H of this chapter.