Principal or Accessory Use. Antennas and towers may be considered either principal or accessory uses. A different existing use or an existing structure on the same lot shall not preclude the installation of an antenna or tower on such lot. For purposes of determining whether the installation of a tower or antenna complies with district development regulations, including but not limited to setback requirements, lot coverage requirements, and other such requirements, the dimensions of the entire lot shall control, even though the antennas or towers may be located on leased parcels within such lots. Towers that are constructed and antennas that are installed, in accordance with the provisions of this article shall not be deemed to constitute the expansion of a non-conforming use or structure.