Hey everyone, having a problem burning the max size of a movie with InstantCopy.

In the beginning, I made sure the size of the movie stayed at 4.31 GB as the meter where it shows you how much space it is going to take stayed green. But after the alteration of the movie and right before it starts burning, InstantCopy says to me that my dvd-r doesn't have enough space and needs 4.7 GB, so it gave me an option to truncate it and it went down to 4.48 GB in size. Just wondering why InstantCopy would ask me that when I only set the size of the movie to 4.31 GB and it was good to go? Is there a TOC file or some other file that InstantCopy puts in that I have to account for when i resize the movie? I am using Ritek G03 dvd-r media. Let me know, thanks