rdgrimes- did those scans complete at 16x or drop down to 8x at the defect(s)? My scan of the "CBAD" at 16x did just that.
I couldn't do a C2/CU scan of the "CBAD" at max. speed. I selected the last 4 tracks (with high error rates) and an earlier track to get the reading speed up. The scan always slowed to 8x for the "difficult" part. The same selection with C1/C2 went through at max. rate and (apparently) had some unreadable sectors: this message box popped up repeatedly:

. It's pretty obvious what it's about, but I don't have the fonts or language skills to confirm (no I don't mean the part about "Wiederholen/Abbrechen"

). cfitz?
The grey background of a C2/CU scan is pretty dismal.

Personally, I don't think it's necessary for distinguishing C2/CU from a C1/C2 scan- the legend suffices.
G