Expansion of Use. The facilities shall not have additions to, or enlargements or expansions of the tower structure, except to change, upgrade or add antennae pursuant to subsection B of this section. The facilities may have additions, modifications, strengthening or rehabilitation of the tower structure and/or accessory building(s), greater than ten percent of the existing structure/building, subject to the review and approval of the planning commission pursuant to subsection F of this section. Any proposed addition, modification, rehabilitation, relocation or reconstruction less than ten percent of the existing structure/building are subject to the review and approval of the director of community development pursuant to Chapter 18.12 of this title.