Ricoh MP9120 12x burned TDK Reflex Ultra (TDK Corp) tested with LiteOn 48246S at 24x on Kprobe 1.1.16:

I had to cancel the test (at 99%), because at the end LiteOn started slipping constantly and would advance to next LBA very slowly. It appears the end of the disc is damaged according to LiteOn/Kprobe.
However, the same disc tested with Plextor Premium (fw 1.03) with Plextools Pro 2.05:

As you can see, there are C2 errors that are not there on the LiteOn scan (c. 53 mins mark). Furthermore, the tracking errors that cause LiteOn to slip at the end of the disc (c. 78 mins) and produce C2 errors are not there on the Plextor scan.
Furthermore, the disc is totally unreadable in Windows Explorer on LiteOn 48246S. Nero CD Speed's ScanDisc/Surface Scan gives the value 'damaged' for the very last block of the disc when tested on the same drive:

On Plextor Premium the situation is the same: disc not readable in Windows Explorer and ScanDisc Surface Scan shows only the last block as 'damaged'.
There are two anomalies here:
1) Plextools Pro does not report the end of the disc to contain any CU errors (nor C2 for that matter). However, the disc remains unreable in all drives tested (directory/contents data part of the disc is unreadable?) and last block is reported as 'Damaged' by Scan Disc.
Likely explanation: Either Plextools or Premium misses the reporting of C2 errors on that part of the disc.
2) Plextools Pro reports C2 errors at c. 53 minutes on the disc. However, Scan Disc on the same drive (or any other drive) does not report any block as "damaged"
Likely explanation: What Premium/Plextools flags as C2 errors is not flagged as such by Nero CD Speed's Scan Disc test. Another (unlikely?) explanation is that Premium generates random C2 errors on its own.
Are there any other possibilities?
Am I testing something wrong or is the Premium/Plextools Pro test inaccurate when testing the end of this particular disc?
I will report this to Plextor if my findings are considered to be valid.
Best regards,
Halcy