I got your e-mail and went back to some old notes of mine. It turns out I did have a bit of roll-off happening near the upper end of the scale (albeit not quite as pronounced as yours, which is probably why I didn't remember it being there). I suspect that we're both seeing a roll-off in the test tone sweep (understandable, since by that point you've moved beyond the 120Hz limit of the equalizers).

For reference, here's ted_b\'s curve and a largely unadjusted curve from my system (my file's a bit large, sorry - didn't resize or anything).

By the way, ted_b, that's a really slick looking setup you have! ( Room layout and front of room .)