I need some comments on this picture:

I have burned 25 of these Arita 8x ritekG05 discs and all the previous burns have been good. I mean my LG4120B (A111 F/W) has burned em 4x and with nero cdspeed I have gotten results like 4x --> 10x speeds.
But now this, I dont know what kinda conclusion I should make, the data works allright but my drive reads it much slower. This has been the case with 4 discs in a row so it cannot be just and coincidence. Any comments?
update:
I really think it was just a bad batch of Ritek discs. The other 25 tube worked remarkably well but the other 25 tube discs all had bad read performance.
Now I got Bulkpaq (fujifilm03) and Datawrite(fujifilm03) 8x dvd-r media and they burn and read really fast with LG4120B