(1) Notwithstanding anything contained in section 17, the assessment for the period upto the 31st day of March, 2005 in respect of any registered dealer, who falls under any of the categories mentioned in sub-section (4) of the said section as it stood on the 31st day of March, 2005 and who has filed returns and paid tax in accordance with the provisions thereof, pending on the 1st day of April, 2006 shall, subject to the provisions of sub-section (2), be treated as completed.

(2) Notwithstanding anything contained in sub-section (1) where the Commissioner or the Deputy Commissioner, as the case may be, is satisfied on information or otherwise, that a registered dealer,-

(a) has concealed any sale or purchase; or

(b) has furnished incorrect statement of his turnover or incorrect particulars of his sales, in the return submitted under section 17 or otherwise, relating to an assessment made under sub-section (1), which has resulted in reduction of the amount of tax payable by him under this Act in respect of any of the periods, the Commissioner or the Deputy Commissioner, as the case may be, shall, within five years from the 1st day of April, 2006, direct the assessing authority to reopen the assessment for such period after giving such dealer a reasonable opportunity of being heard and to make fresh assessments following the procedure under sub-section (3) of section 17, for that period to the best of his judgement and the time limit specified under section 19 shall not apply to such fresh assessment.

(3) Where on reopening of an assessment under subsection (2), it is found that the amount of tax, if any, paid by a dealer is less than the amount of tax, which he is liable to pay on such fresh assessment, the assessing authority shall direct such dealer to pay the difference between the amount of tax already paid and that arrived at on such fresh assessment, together with thrice the amount of such difference as penalty:

Provided that no penalty shall be imposed under this sub-section on a registered dealer, in respect of such period, where such dealer voluntarily discovers omissions or errors or other facts resulting in short payment of tax due from him according to books of accounts and furnishes revised return, together with proof of payment of the balance amount of tax and interest under sub-section (3) of section 23, which is found to be payable, on or before the 31st day of December, 2006.