Where an attested copy of a contract between the parties concerned is filed with the application for a building permit, which contract sets forth a valid agreement for joint use of parking spaces for the life of the buildings or uses concerned, the number of spaces required jointly for a place of assembly, the use of which is principally exercised during nonbusiness hours, and a business use or uses regularly closed at such times may be reduced so that the total equals whichever is greater of (A) all the spaces required for the business use or uses plus one-half of the spaces required for the place of assembly, or (B) all the spaces required for the place of assembly plus one-half of the spaces required for the business use or uses. (Prior gen. code § 8-63.14)