Where, in pursuance of any order under this Act, in respect of any period of assessment commencing on or after the 1st April 2004, refund of any tax becomes due to an employer or person he shall, subject to the rules, if any, be entitled to receive, in addition to the refund, simple interest at the rate of six per cent. per annum for the period commencing on the date next following the last date of the period of assessment to which such order relates and ending on the date of such order or for a period of eighteen months, whichever is less. The interest shall be calculated on the amount of refund due to the employer or any person in respect of the said period after deducting therefrom the amount of penalty and interest, if any, charged in respect of the said period and also the amount of refund, if any, adjusted towards any recovery under this Act. If, as a result of any order passed under this Act, the amount of such refund is enhanced or reduced, as the case may be, such interest shall be enhanced or reduced accordingly.

Explanation : For the purposes of this section, where the refund of tax, whether in full or in part, includes any amount of refund on any payment of tax made after the date prescribed for filing of the last return for the period of assessment, then the interest, in so far as it relates to the refund arising from such payment, shall be calculated from the date of such payment to the date of such order.