Avia should be correct, as should the internal test tones on a THX certified receiver, and I'm not sure if your receiver is or not, but we still had the same problem, with similar results. So something isn't right somewhere, either on the Avia disc, or with the receiver. I would reccomend calibrating with Avia, and using those settings for about a week, then recalibrating with the receiver's test tones and see which one you like the best. I found that I am hearing my surrounds and surround back a lot better after calibrating with the receiver's tones.
I can't wait for Avia 2 to come out so I can see if that discs calibrations have the same issue.