Scrutiny and best-judgment assessment govern return discrepancies, non-filing, and registration failures under the cess framework. The proper officer may scrutinise returns and related particulars, point out discrepancies, seek an explanation, and proceed further if the explanation is not satisfactory or corrections are not made in the relevant return. Where a return is not furnished, or where registration has not been obtained or has been cancelled though cess remains payable, the officer may make a best-judgment assessment on available material and issue an assessment order within five years from the relevant month. A reasonable opportunity of being heard is mandatory before passing such an order.