The City Planning Commission, by special permit, may modify:

(a)        the street wall requirements and minimum base heights of Section 91-31 (Street Wall Regulations);

(b)        the setback requirements of Section 91-32; and

(c)        where such zoning lots contain buildings existing on December 15, 1961, that exceed a height of 300 feet, the lot coverage regulations of Section 91-33 and the maximum horizontal dimension set forth in Section 91-34 (Maximum Horizontal Dimension for Tall Buildings), provided such modifications are limited to that portion of the development or enlargement between 300 and 325 feet in height, and provided the lot coverage of such portion does not exceed 55 percent.

In order to grant such special permit, the Commission shall find that:

(1)        such modifications will result in a site plan consistent with existing scale and streetscape patterns;

(2)        such modifications will ensure a harmonious relationship between the development or enlargement and the surrounding area;

(3)        such street wall modifications will enhance pedestrian circulation by providing pedestrian amenities that relieve sidewalk congestion;

(4)        such setback, lot coverage or horizontal dimension modifications will not unduly obstruct access to light and air to surrounding streets and properties; and

(5)        such setback, lot coverage or horizontal dimension modifications will result in a built form that maintains an appropriate relationship between tower and base portions of the development or enlargement.

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