I've just installed QpxTool 0.7.1 and was able to see 4 parameters in Basic Info section of my Plextor PX-755A:
CD Read (HH:MM:SS);
CD Write (HH:MM:SS);
DVD Read (HH:MM:SS);
DVD Write (HH:MM:SS).
The fact is that I also run PXInfo 1.26 and got the same write counters. With PXInfo I wasn't able to understand also the read counters and disc_loaded counter.
Anyway, having the same info from two applications, makes me believe that QpxTool also give write and disc loaded counters in a correct way.