Except for the use of land with minor improvements, in C6 or C8 Districts, a non-conforming use listed in Use Group 17 or 18, or in C8 or Manufacturing Districts, a use listed in Use Group 11A, 16, 17, or 18 which is non-conforming with respect to the applicable district regulations on performance standards, may be enlarged or extended, provided that:

(a)        such enlarged or extended portion does not occupy more than 25 percent of the floor area or space which such non-conforming use occupied or utilized within the building or other structure at the time when it became non-conforming; provided, however, that in no event shall any such enlargement or extension create a non-compliance or increase the degree of non-compliance of a non-complying building or other structure; and

(b)        such enlarged or extended portion conforms to the applicable district regulations on performance standards and on accessory off-street parking spaces and loading berths, as set forth in Section 52-41 (General Provisions).

In the specified districts, such use may be extended into any floor area where it would be permitted as a changed use under the provisions of Section 52-35 (Manufacturing or Related Uses in Commercial Districts), provided that the applicable district regulations on performance standards and accessory off-street loading berths, as set forth in Section 52-41, shall apply to such extended floor area.