In M1-1 Districts in designated areas in Subarea 1, as shown on the maps in APPENDIX J (Designated Areas Within Manufacturing Districts) of this Resolution, for any zoning lot containing a self-service storage facility that meets the requirements of paragraphs (a) or (b)(1) of Section 42-121 (Use Group 16D self-service storage facilities), the maximum permitted floor area for commercial or manufacturing uses on the zoning lot pursuant to the provisions of Section 43-12 (Maximum floor area ratio), inclusive, may be increased by a maximum of 25 percent of the lot area or up to 20,000 square feet, whichever is less.