AutoFit function not working?

[CBC]

I've noticed that several of my finished avi conversions had ended up less than 4GB in size, even after I select AutoFit. Aren't they supposed to fill up a standard DVD-5 if this is selected? Also wanted to confirm that you can only select AutoFit right after you've started the "Quick DVD" process, as it's greyed out any other time before that point.
My preference would be to have the most quality I can get to fill the DVD-5 if I select AutoFit .Or am I misunderstanding the function of autofit?

[Jikchung]

Autofit should fill the disc if you have long enough play length(s). I have noticed on some NTSC(film) type AVI files I come out undersized as well. Posted here: https://www.videohelp.com/forum/viewtopic.php?t=269159
and emailed logs to Chris but have yet to hear back, this could be something already fixed and awaiting next release.

[CBC]

Hopefully, although even this version he sent me just yesterday to try out the shut down feature still does it. Here's hoping it will get addressed in a future build.