The concave is just my personal theory. After seeing all the combining problems and the changes from the 470 to the 470R, I learned how much difference the concave makes. All American concaves (CNH, JD, AGCO) are wire concaves. That's what the 470R got. It improved the corn combining very much, but not wheat. So my theory was, if one could close the lexion concave to zero (there must be a reason why everybody else does that) and the concave radius would matche the cylinder radius, like on other colors, the lexion might be able to thresh the heads on US wheat as good as the other colors. If one would than increase the cleaning capacity on the 470 to reduce the grain loss, it might keep up with a 9650 STS. If one would put a wire concave under the APS, to get rid of the grain, that the APS threshes out, one could probably reduce the cracking, too. Right now I think this thing in front of the cylinder with that fancy name is nothing but a straw shredder overloading the cleaning system with MOG. Again, this is my theory after many hundred CASE hours, well over 1100 lexion hours and many more Deere combine hours. I also know that in certain conditions the lexion setup might work better, as I've been told by Canadian pen friends.