Limitation on notices: time limit to serve notice after return; intimation treated as an order for assessment purposes. Amendment to section 16 restricts service of notices under sub section (2) so that no notice may be served after the expiry of twelve months from the end of the month in which the return is furnished, and inserts an Explanation that an intimation under sub section (1) or (1B) shall be deemed to be an order for the purposes of the provision dealing with orders under section 25.