For zoning lots with existing buildings to remain:

1. only the portion of the zoning lot containing a development or ground floor level enlargement shall be considered for the purposes of applying the regulations of  Sections 32-31, 32-32 and 32-33, inclusive; and
2. only the portion of the zoning lot frontage associated with the building containing the alteration or change of use shall be considered for the purposes of determining the applicable regulations of Section 32-34.