I noticed in the first screen shot you posted, that you were encoding to 23.97 but later post was 29.97. Was the 23.97 an error? Looks like source footage is 29.97 right?
When encoding MPEG-2 DVD in AME, a good way to estimate encoding rate is 560/minutes = rate. Your example of 115 minutes comes out to about 4.8 data rate, maybe go 4.7 for safety. For shorter vids, consider 8 as a max rate for video (audio gets added on top of that).
Thanks
Jeff Pulera
Safe Harbor Computers