Unless otherwise restricted by application of regulations in Section 415.240, Air Navigation Space Regulations, the total height of any structure authorized by conditional use permit, not including a wireless support structure, disguised support structure, or substantial modification thereof authorized by a conditional use permit, including roof top mechanical equipment attached to such structure, shall be authorized by specific conditions of the permit, but shall not exceed two (2) stories or thirty (30) feet in height, whichever is less, above the average finished ground elevation at the perimeter of such structure. A public utility tower authorized by a conditional use permit may be erected to any height not in conflict with the application of regulations in Section 415.240, Air Navigation Space Regulations.