are you absolutely sure about non-existent 2x DVD-R media? can it just appear remarked DVD-R 1x? what about DVD+R 2.4x, can they be written at 2.4x with PX716A?
anyway I have to say that recording quality of cheap media was really improved in fw 1.05. I've tried disks like Esperanza, TDK (grey), Sky and other 4x/8x media below 50 cents per disk - quality become Very Good or even Excellent if checked in Q-Check TA Test and 20-30% less PIE in PI/PO Test