For neighborhood places of worship, the principal use shall be the holding of regularly scheduled religious services. Accessory facilities and functions, such as classrooms, social halls, administrative offices, bath and shower facilities, gymnasiums and indoor recreation facilities, may be provided, however, such facilities and functions individually shall not exceed 20% of the building's gross floor area, and in aggregate shall not exceed 50% of the building's gross floor area. A social hall for use by congregants following services, located in a basement, may exceed the accessory facilities limitation above in the event that it is not used concurrently with the primary worship space, but in no event shall it exceed the area of the primary worship space. No building permit or certificate of occupancy shall be granted to such accessory use, building or structure until the building permit and certificate of occupancy for the principal use or building, respectively, have been granted. A school of general instruction established at the site of a neighborhood place of worship shall not be considered as accessory to the neighborhood place of worship, but rather as an additional principal use. Where a school of general instruction and a neighborhood place of worship are located on the same lot, the cumulative minimum lot area of each principal use shall be satisfied.