Quick Copy Changes Remaining Time By Disc Brand???

I used 8X TDK blanks with Nero Quick Copy in Nero Express. Disc to Disc. The time starts out around 7:36 or so remaining on nearly EVERY disc I have tried. But the burn always ends around 10 minutes or more. When I tried JVC 8X blanks the burn starts the same 7:30 or so then ends with the total time of 15:30. same speeds different brands of discs. Try this one? Nexxtech 8X speed blanks start at 7:36
and end at 7:36. WTF? Used read buffer @ 50%, buffer level skyrocketing though sometimes peaks around 94%, never seen that before. Tried HP 16X discs HA! they start at 4:40 remaining end at
past 11:00 total time. HA! Stumped?? Me too HELP!!! What did I do to my Nero?