(1) Where by reason of some collusion or a deliberate act any tax or charge has not been levied or made or has been short-levied or has been erroneously refunded, the person liable to pay any amount of tax or charge or the amount of refund erroneously made shall be served with a notice, within five years of the relevant date, requiring him to show cause for payment of the amount specified in the notice.

(2) Where, by reason of any inadvertence, error or misconstruction, any tax or charge has not been levied or made or has been short-levied or has been erroneously refunded, the person liable to pay the amount of tax or charge or the amount of refund erroneously made shall be served with a notice within three years of the relevant date, requiring him to show cause for payment of the amount specified in the notice:

Provided that, where a tax or charge has not been levied under this sub-section, the amount of tax shall be recovered as tax fraction of the value of supply.

(3) The officer of Sales Tax empowered in this behalf shall, after considering the objections of the person served with a notice to show cause under sub-section (1) or sub-section (2), determine the amount of tax or charge payable by him and such person shall pay the amount so determined.

Provided that order under this section shall be made within ninety days of issuance of show cause notice or within such extended period as the Collector or, as the case may be, Collector (Adjudication) may, for reasons to be recorded in writing, fix, provided that such extended period shall in no case exceed ninety days:

Provided further that where a registered (***) person is served with audit observation, the period of,—

(i) five years prescribed in sub-section (1); and

(ii) three years prescribed in sub-section (2),

for the issuance of show cause notice shall be treated as extended from the date of serving of audit observation (s) to the date of issuance of show cause notice.

(4) For the purpose of this section, the expression "relevant date" means--

(a) the time of payment of tax or charge as provided under section 6; and

(b) in a case where tax or charge has been erroneously refunded, the date of its refund.