Bad GO5 media from Shop4Tech

I used 100 G04 Riteks with really good results. I am somewhat of a newbie to this forum so bear with me. My CD speed from nero always showed an average of about 10 to 20 on the PI errors and really low on the PI failures. The G05’s I burned (even using the same burn speed 4X) were really out of whack. They had a “hill” (hit 70)of errors in the beginning and leveled off in the 20’s after that on my NEC 2510a. When I burned on my Liteon 4x don’t know the model number, it was in the 200’s. I have since tried a the 2.17 firmware for the NEC with no better results. Is this just a bad batch? It seemed to play okay in my home DVD player but I expected better results.