Deeming of proper officers permits GST officers to exercise corresponding SGST/CGST powers with notice and coordinated proceedings. Deeming provision designates SGST/CGST officers as proper officers for corresponding provisions of this Act, subject to rules limiting scope and conditions. An officer acting under this Act may simultaneously exercise corresponding SGST/CGST powers as part of the same order, with an obligation to intimate the jurisdictional SGST/CGST officer. Rectification, appeal and revision from such cross-authority actions lie before the officer appointed under section 4, and duplicate proceedings under this Act are barred where a SGST/CGST officer has already initiated proceedings on the same subject matter.