In the NEC, not in the Benq! The "problem" (which isn't one) is between NEC 6X/8X burns and Benq scanning. NOT with 8X burns "in general".
Really there is no reason to consider it an issue. As I mentioned above, all my NEC 8X burns show similar figures in Benq scans, though the PIE increase doesn't appear in LiteOn scans, and the jitter increase doesn't appear in Plextor scans. Get my point?
If it makes you feel better, just burn your TYG02 @8X or even @12X in your Benq 1620, the scans will be nicer than when burnt in the NEC. But don't expect 99% QS and <9% jitter for all burns, these are extremely high standards to say the least.
When scanning NEC burns in Benq drives, just forget about this jitter and PIE reporting.