Within Area B-R3 on the maps in the Appendix to this Chapter, where a special permit by the City Planning Commission on a receiving site is sought pursuant to Section 89-21 (Transfer of Floor Area from Hudson River Park), and the bulk regulations of the underlying C4-7 District apply pursuant to the provisions of Section 89-11 (Use and Bulk Regulations on Receiving Sites), the floor area ratio for qualifying affordable housing shall be 12.0 within a Mandatory Inclusionary Housing area, and such maximum residential floor area ratio may be increased to a maximum of 14.4 as set forth in Section 89-21.