Beautiful room and system, congratulations. If it were mine, I would try a couple of the Diffuser panels from Acoustic Revive . They are more versatile than many of the room tx's and do many things depending on where you place them. I would try them on the sides, behind and also on the backwall and see how each position effected the sound. It could give you an idea of where the issue is too. They can stand on their own or be hung and are not too out of line with your decor. Furutech also makes some.
Maybe I missed it but were the cables and power treatments the same in the dealer's system?
Maybe I missed it but were the cables and power treatments the same in the dealer's system?