My cousin runs two sts deere machines, a 9660 and a 9670. He is very loyal to green machinery. His only real complaint with the 9660 is rotor loss in corn. I'm sure it is worse in some fields or varieties, but he says that he would like to be able to reduce the amount of rotor loss he gets. I'm pretty sure that the rotor is set up the way it would be from the factory, and he is running round bar concaves. In this area the corn may run any where from 150 bpa to 200 or better. The 9670 has yet to be run in corn as it is new this year. Any suggestions would be welcome, as I am more used to axial flow machines.