@ArtMaster, removing the main speaker feed from your sub was a good move, but it looks like your sub still has some filtering being applied. Turn up the crossover knob as high as it will go (or to bypass). You want the sub to send its full frequency range to the MRX. This way, combined with the change you already made, the MRX will be handling all of the bass management. ARC allows it to do a much better job than knobs and extra connections on the sub.
You should also probably turn down the LFE volume level (gain) on the sub somewhat. As it is, the MRX is having to cut the sub volume and boost your other speakers. Try turning the gain to about 9 o'clock (assuming it is around 12 o'clock now). After these changes, you'll need to re-run ARC. Then post your new charts and targets.