I see the problem here too.
I want more for my data backup to last (who doesn't), and the set top won't help much there
My external EW162i doens't support cd-speed media check very well, and no pif is shown.
I have run Qscan a few times, at the same speed on the same disk. The results were very similar, other than the whole graph being moved up a small amount. I use a viewer on the 2 pics and just flipped back and forth, and the the fact it was the same disk stood out better to me that way.
If with cd-speed they were the same, except for a spike near the end, then i would be worried about fingerprints or in a few years it could be rot or scratches I guess.
If I can't use the tools this way, then I can delete the scans I've saved and free up some disk space.
Probably in 5 years I'll be out of the red light area and into the blue so it won't matter maybe