A nonconforming use shall not be expanded or enlarged, except in accordance with the provisions of this section.
(a) The floor area of a nonconforming residential use located within a Manufacturing or Commercial District may be expanded by up to twenty-five percent of the original floor area already in nonconforming use. However, no expansion shall be permitted that would increase the number of dwelling units.
(b) The floor area of a nonconforming use may be expanded, and the land area of a nonconforming use may be enlarged, to permit compliance with off-street parking, off-street loading and performance standards which may apply.