I saw that offer at FutureShop and said to myself, "Should I?"
I elected to pass because I'd had no experience with that media and it was an awful lot to buy without knowing in advance what to expect. And, it's not on the Plex recommended list. Not that it helps now, but a good practice is to buy media in small quantities (singles or 5-packs, say), try it out, then go for the big quantities if it works out OK.
You might want to try "scan disc surface" in Nero CDSPeed, but running SUM-8 and SUM-1 PI/PO tests in Plextools should give better info as to what's happening with these burns. Or, you can try reducing the burn speed - if Nero (or whatever) allows burning at 8x, try reducing it to 4x. I've also had improved burns by running the Focusing/Tracking (FE/TE) test prior to burning on non-recommended media.
The fact that you have success with recommended Maxell media and problems with non-recommended Daxon media seems to point to the media and not your 712, but if you get back to us here with more information about the burns you did, we can let you know if your nephew is about to receive 190 free blank DVDs or not...