If defined as part of any special exception approval, said special
exception use shall be completed within the identified time frame.
Also, the Zoning Hearing Board may grant an extension of time for
any completion date if the applicant or his agent requests such an
extension and if good cause for the extension is shown. If, at the
end of the identified time frame or extended completion period, the
special exception use is not completed, and if no extension has been
granted, the approval of the special exception use shall be null and
void.