The City Planning Commission may permit an increase in the number of spaces in an accessory off-street parking facility existing prior to May 8, 2013, as listed in paragraph (a) of Section 13-45 (Special Permits for Additional Parking Spaces), provided that, in addition to the conditions and findings set forth in Section 13-45, the Commission shall find that:

(a)        where such increased number of permitted off-street parking spaces in such existing parking facility would serve the parking needs of a zoning lot or zoning lots comprised predominantly of residential uses, either:

(1)        finding (a) of Section 13-451 (Additional parking spaces for residential growth) is met; or

(2)        the sum of any existing off-street parking spaces, and the proposed increase, does not exceed:

(i)        20 percent of the total number of dwelling units, where such units are located within Community District 1, 2, 3, 4, 5 or 6; or

(ii)        35 percent of the total number of dwelling units, where such units are located within Community District 7 or 8; and

(iii)        the number of parking spaces that would be permitted for existing conforming non-residential uses, if the ratio of parking spaces to floor area for the applicable use, as specified in Section 13-10 (PERMITTED OFF-STREET PARKING IN THE MANHATTAN CORE), were applied.

Any dwelling units on the zoning lot or zoning lots which are non-complying as to density shall not be included in such calculation pursuant to paragraphs (a)(2)(i) or (a)(2)(ii) of this Section, and any non-complying floor area on such zoning lot or zoning lots shall be excluded in applying such ratio in paragraph (a)(2)(iii) of this Section; or

(b)        where an increased number of permitted off-street parking spaces in such existing parking facility would serve the parking needs of a zoning lot or zoning lots comprised predominantly of conforming non-residential uses, the sum of any existing off-street parking spaces, and the proposed increase, does not exceed the number of parking spaces that would be permitted if the ratio of parking spaces to floor area for the applicable use, as specified in Section 13-10, were applied. Any non-complying floor area on such zoning lot or zoning lots shall be excluded in applying such ratio.