(a)        In C1 and C2 Districts mapped within R6 through R10 Districts with a letter suffix, and in C1-6A, C1-7A, C1-8A, C1-8X, C1-9A, C2-6A, C2-7A, C2-7X, C2-8A, C4-2A, C4-3A, C4-4A, C4-4D, C4-4L, C4-5A, C4-5D, C4-5X, C4-6A, C4-7A, C5-1A, C5-2A, C6-2A, C6-3A, C6-3D, C6-3X, C6-4A or C6-4X Districts, residential buildings shall comply with applicable bulk regulations for Quality Housing buildings set forth in Article II, Chapter 3, except as modified by Section 34-20 (EXCEPTIONS TO APPLICABILITY OF RESIDENCE DISTRICT CONTROLS). In addition, Quality Housing buildings shall comply with all of the requirements of Article II, Chapter 8 (Quality Housing Program).

(b)        In C1 and C2 Districts mapped within R6 through R10 Districts without a letter suffix or other Commercial Districts with a residential equivalent of an R6 through R10 District without a letter suffix, the bulk regulations applicable to Quality Housing buildings set forth in paragraph (a) of this Section may, as an alternative, be applied to a building under the same conditions set forth in Sections 23-011 and 34-112.

(c)        In Commercial Districts, for Quality Housing buildings in which at least 50 percent of the dwelling units are income-restricted housing units, or at least 50 percent of its total floor area is a long-term care facility or philanthropic or non-profit institution with sleeping accommodation, the applicable bulk regulations of this Chapter may be modified for zoning lots with irregular site conditions or site planning constraints by special permit of the Board of Standards and Appeals, pursuant to Section 73-623 (Bulk modifications for certain Quality Housing buildings on irregular sites).