Nem, if you were able to previously burn yuden000t02 at 16x in your burners with good results before and consistently, then you managed to get great stock from in-store. If you're not getting that, you're like the rest of us who have to be content with 8x and 12x burns with them. If your burner or burner software has some kind of 'media quality check,' run that test on each blank. After 30 seconds, it will tell you if the media can be burned at its highest speed. If not, it will tell you it can't.
I've gotten in-store y000t02 from Best Buy and Circuit City. I had one 50 pk that let me overburn to 12x every last DVD in the spindle. I had another with no visible defects that alternate 8x and 12x. The Circuit City (Sony DVD+R MIJ) however is straight 8x burns.
As for the slightly o/t of whether it's 'value line' or OEM, that's (respectfully) been shown to only be a marketing thing some retailers have used, as TY does not officially say any TY is either 'value' or 'premium'. Usually, the in-store Fujis/Sonys that are y000t02 burn about as well as the OEM unbranded, if the in-store is of good quality (no dye spotting on the back, which can happen with stuff from BB or CC, so one has to check those when they buy instore).
Also, the instore TY should have a kind of holographic TG or GG number (like ending TG..1158) or so on it, as seen from the back. Also check your blanks for dye spotting. If you have dye spotting, you'll notice more PIFs than normal and that would be partly why the burn speed is lower