NEC 2500A Reading media differently from Sony DRU510A?

Hi guys,

I purchased some RITEKG05 media. Using Dvdinfopro, I selected my nec 2500A and inserted the media to check its info. Dvdinfopro tell me it is a TYG02. I place the same media in my sony dru510A, selected the drive in dvdinfopro, check the media again. It says it is a RITEKG05.

How is it that the same dvd-r is recognized as two different with two very different media code?

Please help?