Recovery of voluntarily disclosed tax deemed due via demand notice; procedural provisions apply and payment treated as tax paid. Outstanding income-tax arising from a voluntary disclosure under section 68 of the Finance Act, 1965 that remains unpaid after the prescribed period is deemed to be tax due on the next day by a demand notice under section 156 of the Income-tax Act; Chapters XV and XVII-D and the Second and Third Schedules apply with the modification that references to one year in section 231 are construed as references to two years. Any such outstanding tax subsequently paid or recovered is deemed to be tax paid by the declarant for the purposes of sub-section (6) of section 68.