Failure to deduct tax at source: deemed assessee in default with interest, asset charge and penalty subject to assessing officer satisfaction. Failure to deduct or pay required tax renders the deductor deemed an assessee in default, subject to a proviso excusing deeming where the payee files a return, accounts for the sum and pays tax with an accountant's certificate; penalty is charged only if the Assessing Officer finds no good and sufficient reasons. Simple interest is payable for the period tax was deductible until deduction and from deduction until payment, interest must be paid before furnishing the prescribed statement, and unpaid tax with interest is a charge on all assets. Limitation for making default orders is prescribed.