Those curves you posted are very impressive. I see the target curves for the front M5s are downward tilting. ARC therefore must be determining the designed response of the speaker and attempting to correct to it for your room. All indications are it did a marvelous job. Does it allow you to adjust the target curve slope?
A-LFR/1000-8 & 2/500v4x2 1000-3,1500-3 100,160,QS10x2,800,M5x2,M2/3/50v4 Air Force, Freedom had v2