(1) The Secretary may, either generally or as otherwise provided by the instrument of delegation, by writing signed by him, delegate to a person any of his powers under Division 10 of Part III or under Part IV.
(2) A power so delegated, when exercised by the delegate, shall, for the purposes of this Act, be deemed to have been exercised by the Secretary.
(3) A delegation under this section does not prevent the exercise of a power by the Secretary.