This is just a guess but from what I can tell from your posts it appears that you have the speakers centered on the long wall firing across the short dimension of the room.
I have done that and the result was aways a loss of upper bass -lower mid range energy. While the speaker measured well in the bass the overall sound was cold/bass shy. What I think occurs is that when the speakers are on the short wall there are a lot more reflections/reinforcements and the bass frequencies sound fuller.
Try moving the speakers to the short wall and see what happens.
I have done that and the result was aways a loss of upper bass -lower mid range energy. While the speaker measured well in the bass the overall sound was cold/bass shy. What I think occurs is that when the speakers are on the short wall there are a lot more reflections/reinforcements and the bass frequencies sound fuller.
Try moving the speakers to the short wall and see what happens.