Summary assessment to protect revenue may be initiated promptly with supervisory approval, deeming handlers liable where payer is unascertainable. A proper officer may, with prior permission of the Additional Commissioner or Joint Commissioner, conduct a summary assessment on evidence of tax liability to protect revenue, issuing an assessment order when delay would harm revenue. If the taxable person is unascertainable for goods, the person in charge is deemed the taxable person and liable. The Additional Commissioner or Joint Commissioner may withdraw a summary order if erroneous and require the matter to follow regular assessment procedures under sections 73 or 74.