In section 28 of the Customs Act,--
(a) after sub-section (1), the following sub-section shall be inserted, namely:-
"(1A) When any duty has not been levied or has been short-levied or the interest has not been charged or has been part paid or the duty or interest has been erroneously refunded by reason of collusion or any wilful misstatement or suppression of facts by the importer or the exporter or the agent or employee of the importer or exporter, to whom a notice is served under the proviso to sub-section (1) by the proper officer, may pay duty in full or in part as may be accepted by him, and the interest payable thereon under section 28AB and penalty equal to twenty-five per cent. of the duty specified in the notice or the duty so accepted by such person within thirty days of the receipt of the notice.";
(b) to sub-section (2), the following provisos shall be added, namely:-
"Provided that if such person has paid the duty in full together with interest and penalty under sub-section (1A), the proceedings in respect of such person and other persons to whom notice is served under sub-section (1) shall, without prejudice to the provisions of sections 135, 135Aand 140, be deemed to be conclusive as to the matters stated therein:
Provided further that, if such person has paid duty in part, interest and penalty under sub-section (1A), the proper officer shall determine the amount of duty or interest not being in excess of the amount partly due from such person.".