In C2 Districts, the provisions of Section 32-422 (Location of floors occupied by commercial uses) shall apply in lieu of Section 32-421 (Limitation on floors occupied by commercial uses). In addition, the provisions of Section 32-422 shall be modified such that the limitations set forth in paragraph (a) of such Section need not apply, and the requirements in paragraph (b) of such Section shall apply only where commercial uses are located above any story containing dwelling units.