Accessory off-street parking spaces for existing or new governmental offices may be located on a zoning lot other than the same zoning lot as the use to which such spaces are accessory, provided that:

(a)        such spaces are located within Subarea H and in a facility, or portion thereof, that is entirely below curb level;

(b)        the portion of such facility beneath the required public plaza area shown on Diagram 3 in Appendix A of this Chapter is sufficiently below curb level so that trees may be planted at curb level within such public plaza but is in no case less than four feet below curb level; and

(c)        no more than 377 spaces are provided within such facility.

For purposes of this Section, the governmental offices on Block 688, Lots 1001-1002, as of June 23, 2005, may have up to 377 accessory off-street parking spaces in such facility.