Use DVD Shrink. The reauthor function.. you can select a specific chapter under 'Set Start And End Frames' as circled in red here: http://members.cox.net/freddiemercury/shrink.gif
And you can adjust it by frames either way also if the chapter marks aren't exactly where they should be :)
Get DVD Shrink here: http://www.mrbass.org/dvdshrink
It's no longer updated, but very useful software.