Where an order determining the amount due from an employer under Section 7-A or Section 7-B has been passed and if the officer who passed the order-
(a) has reason to believe that by reason of the omission or failure on the part of the employer to make any document or report available, or to disclose, fully and truly, all material facts necessary for determining the correct amount due from the employer, any amount so due from such employer for any period has escaped his notice ;
(b) has, in consequence of information in his possession, reason to believe that any amount to be determined under Section 7-A or Section 7-B has escaped from his determination for any period notwithstanding that there has been no omission or failure as mentioned in clause (a) on the part of the employer,
he may, within a period of five years from the date of communication of the order passed under Section 7-A or Section 7-B, reopen the case and pass appropriate orders re-determining the amount due from the employer in accordance with the provisions of this Act :
Provided that no order re-determining the amount due from the employer shall be passed under this section unless the employer is given a reasonable opportunity of representing his case.