I have this movie, and if there is an experiment you want to run, say within the next week, lemme know.
So, if you have "2.2" (misnomer, but it's easy) . . . you still get LFE? Just curious. For "stereo" means no LFE, at least as far as terminology.
I wonder if some setting in the player, like "2ch pcm downmix" would sound any different. You'd probably lose a lot of LFE(?).
For the very few comparisons I've made with accompanying lossy tracks, they almost all sound about identical to me. However, every once in a while, there is a big difference (which leads lead me to believe it's a different master), and one of them is the Dark Knight.
The first thing I thought of when seeing your thread, was autoflagged DRC (and a bad implementation of it, such as with Iron Man) from a TrueHD track, but this title doesn't have that, so it can't be it.
Lastly, some movies are just mixed a lot louder than others.
Sorry, I don't know what to say.