For zoning lots in R3-2 Districts, as well as R4 and R5 Districts without a letter or number suffix, the City Planning Commission may authorize modifications to the applicable height and setback regulations for residences, provided that the conditions of paragraph (a) and the findings of paragraph (b) are met.

1. Conditions and limitations
   
   The height modifications shall not apply to buildings utilizing the optional provisions for predominantly built-up areas set forth in Section 23-71, inclusive.
2. Findings
   
   The Commission shall find that:
   1. where the height modification is proposed for a zoning lot containing qualifying senior housing, the additional floor area permitted for the use is accommodated in an efficient manner;
   2. where the height modification is proposed for other residences, by concentrating permitted floor area in a building or buildings of greater height, the preservation of an existing building, topography, vegetation, or view corridors having environmental, historic or aesthetic value to the public will be assured, and that such preservation would not be possible by careful siting of lower buildings containing the same permitted floor area;
   3. such modification is the least modification required to achieve the purpose for which it is granted;
   4. the proposed modification does not impair the essential character of the surrounding area; and
   5. the proposed modification will not have adverse effects upon light, air, and privacy of adjacent properties and of any existing buildings on the zoning lot.

The Commission may prescribe appropriate conditions and safeguards to minimize adverse effects on the character of the surrounding area.