'50. As pointed out earlier, in cases where mismatch occurs, it is a starting point for an enquiry. The first phase of enquiry should be at the Department level, as in most cases, both the dealers are registered in different assessment circles. The Court has come across cases, where such mechanically drafted show cause notices have been sent by Assessing Officers without embarking upon any enquiry, even though the other end dealer is also registered within his jurisdiction. Thus, when the Assessing Officer has data to show that the dealers registered with him, whose returns have been accepted when compared to the other end dealer does not match, then the Assessing Officer is first required to enquire with the Assessing Officer of the other end dealer to make verifications as to whether the mismatch could have occurred due to any one of the factors, which may not be due to the deliberate default of the dealer, satisfy himself that and after such verification, it prima facie appears that the returns to be revised, at that stage, the Assessing Officer would be entitled to issue a show cause notice containing full particulars and clearly stating as to what was the scope of enquiry done by him and why he is of the prima facie view that the dealer has failed to file proper returns or suppressed information. It is only then the dealer would be in a position to putforth his defence and demonstrate as to how this prima facie view is without any basis.'