Duplicate Disc vs Imports Tracks

[MrDelicious2]

Ok, here is a issue that I've always had since I bought, MTU. Overall, I am very happy with the program...the only issue I can find is the Duplicate Disc option...I can't seem to get a good disc from it. If I import the tracks, then do a custom assembly(write discs now)..the discs copy fine. If I try to use the duplicate discs option...I've never gotten a good disc. I started with 2.612, now I have 2.613 & plextor px-760a. Anyone know why I can't duplicate from disc to disc? Thanks...