The enhanced shoe certainly was an improvement, and the lower sieve seal and a triangular opening cover that were originally part of the Air Flow Control have now been added at the factory. (the factory lower sieve seal is metal whereas I use a rubber seal) These attempts at controlling the air don't address the main air loss areas as you'll see in the video on the website. The maximum air, and whether the CIH or NH fan has higher maximum airflow isn't the issue. Once the Air FLow Control is put in, operators consistently report that the needed fan speed is about 100 RPM less than they'd been running (CIH or NH, doesn't matter). The lower air speeds help let grain thru the sieve but still keep MOG suspended and headed out. Changing crop conditions just don't impact air flow as much once the seals are in place. It's my impression that the improvement is at least as much on the CIH vs NH machines but improvement is significant in either brand, which is what you'd expect given the fact that the shoe design is the same. I don't think that there's much difference in the amount of improvement in the 52" or 62" shoe but it I had to pick on, the 62" shoe is helped more.