Quality and episodes

I have a question about the quality indicator that appears in the customise menu.
I have a 4 episode disc I want to customise and I have the 4 titles opened.
Checking title 1 gets a quality of 100% 2660MB - 2600MB.
Adding title 2 gets a quality 86% 4976MB - 4300MB.
That all makes sense.
However adding title 3 doesn’t further reduce the quality, and the same when adding title 4. It remains as it did with titles 1 and 2 checked. Shouldn’t it contine to reduce in quality as I add more titles?
Also, if I check title 1 and then add title 3 it stays at quality of 100% 2660MB - 2660MB. This is despite the fact that title 3 is 2679 MB in size.
My intention was to use the quality setting to determine how many episodes etc to put on each disc, but I am clearly missing something in understanding how to read it.

If the titles you add use the same VOBs as the others the percentage will not change. I’ve seen this on discs whose menu has a “Play All” option, also when the video+director’s commentary is a different title but uses the same video, just with a different audio track. ALways have PathPlayer in the Always Enable mode when doing episode discs so that the titles will be in playback order. Not sure exactly what you are seeing there. What TV series is it?

Thanks for the info.
Its Rome

Tell me which volume/episode/disc number it is and I’ll see if I can find it to try it out and see if it does the same thing for me.