I had this same results as Michael when I calibrated for all eight spots.
My mom and I measured and marked each location with a piece of tape on the floor, then I placed the microphone (I taped it to the top of my father's camera tripod which was adjusted to ear level (when sitting)) in each spot and calibrated.
It was over a year ago that I ran Audyssey, but if memory serves me correctly, I'm pretty sure it's highly recommended to use a tripod or something of the sort to hold the microphone, rather than sitting in on a chesterfield or holding it in your hand, because objects nearby (especially a wall) will cause reflections that will result in an improper calibration.
