@ [B]the original poster[/B]: I guess most of your confusion comes from the fact that you’ve originally been caught into the usual illusion that scanning is [I]measuring[/I] something on a disc. Am I wrong?
I’m starting to think that disc quality scanning shouldn’t really be taken too seriously
Way to go!
Welcome to the real world, [B]scanning is not measuring anything on the disc[/B]. It’s a report of what happens in a given drive at the error correction stage while parsing ECC blocks. “Things” on the disc like jitter, surface defects, reflectivity, tilt (= flatness), tracking etc… will show (or not…) as PIE/PIF.
Different drives will choke on different kinds of “trouble” on discs, so ALL drives (and yes even of the very same make, models etc…) will report different PIE/PIF plots for the same disc. It’s only normal, and even 100% expected.
That’s why I came more and more to consider that the really best discs/burns are the ones that scan OK in [I]any[/I] scanning drive, rather than those that scan excellently in a “reference” drive like a Lite-On but possibly badly in other drives.
Professional scanning machines are tightly calibrated to give controlled, compliant and comparable PIE/PIF plots. Even so, two passes are not identical. So don’t ask too much of our cheap end-user drives…
Just for the record, this post of mine doesn’t mean that I find scanning useless. Not in the least.