Nero overburning with Benq dw1620

Hey guys, I just bought a Benq dw1620 burner, and when I tried to burn a 4.6+ gig file onto a dvd that can support up to 4.7 gigs, the nero program said that I can’t burn past 4.5 gigs. Is this something wrong with the program or the burner or DVD (HP dvd+r 8x 4.7gig)?