Hi tWreCK, welcome to CDFreaks!
You can find information about interpreting PIE/PIF scans here:
Interpreting PI/PO error scans (stick thread)
We also have an entire forum dedicated to discussing media testing:
Media Testing/Identifying Software (forum)
The "quality score" calculated by Nero CD-DVD Speed is based only on the maximum PIF value, so experienced users tend to ignore that and look at the graphs instead.
The maximum PIF should be 4 or less on a LiteOn scan, with a maximum of 2 being quite common for good burns. The maximum PIE should be 280 or less. but it's usually much lower than that. Lower totals are better.
It's unclear how accurate jitter scans are on these drives, and it will depend on the scanning speed. As a rule of thumb I wouldn't accept any jitter above 12% and for a good burn it should be 10% or lower.
Just as for PIE/PIF scans, different drives can report different levels, and there will also be some variation between scans.
And whether the scanning interval is 1 ECC, 8 ECC or something else.
For drives that can report POF the quality score will be zero if POF > 0.