Well all these type of errors as mentioned are not really there on the disc directly.
Checking between some of mine Lite On 52327S K-probe, Plextor Premium and CDA 3000 scans.
You can have that the LIte 52327S and the plextor premium can report 0 C2 errors while the CDA 3000 reports some E12 errors.
This is caused by the difference in readers.
Also it's a bit more tricky if I'm right.
What does a drive report back as CU and what as C2.
According to the defintion standards:
CU is a unreadable.(E32)
C2 are E12 E22 and E32
C1 is E11,E21 and E31
(NOte a E31 might show up as a E12 on some occasions. That's why E12 errors are most times higher as E31. )
That's the theory
In reality on consumer drives it's the following:
It seems that some drives might report C2 might only report the errors they couldn't correct for C2 which are E32.
And it seems that some drives might report E22 and E32 and not E12 as C2.
Plextor discloses what the Q-Check C1/C2 Test is reporting in the Plextools Professional help file.
C1: indicates BLER, which is the number of E11+E21+E31.
C2: indicates the number of E22.
CU: indicates the number of E32.
These are the number of frames that have correctable or uncorrectable errors, counted per second.
So plextools doesn't count E12. It may encounter those errors but it will not report them. So 0 C2 doesn't mean that it didn't encounter no E12 errors on plextor writers with plextools.