This morning, Michael R posted his curves of TMY-2 (same batch as mine) here:
http://www.apug.org/forums/forum37/1...ntrate-51.html

He got the same boomerang shape, with the inflection in about the same place. So that shape is really there, and was not my mistake. But as another poster pointed out, I hope the slope-change is small enough that most people won't be bothered by it.

Mark Overton