Yes it seemed to make a significant difference in corn. Last year in S ontario, our corn did not quite finish off properly due to a very cool and backward sept. This caused some lower test weights and fragile kernals. We installed the swept back paddles and it lowered our fines by .3-.5%. These paddles have been on the combine ever since and have not created any problems with feeding. I had some good yielding wheat (120bu/acre) and we are now into very high yielding corn (200++) and don't see any ill effects in feeding.
The edible been slow down kit gives you the 320rpm setting and I think it is also a field installed option. I have never change the speed from the 320rpm, or changed back the paddles to the straight ones.
No doubt there is conditions that warrent a higher FAST speed, but not in our crops and conditions. I know many other operators around me who have also had similar experience.
We deliver to 2 different elevators and after we got things set, we had the best grades being delivered. Some other operators had similar grades, but none that I know of that were better. I use the elevator as a pretty accurate barometer as to how we are doing interms of settings. So far, my experience has been that I can consistantly be the cleanest loads delivered. I am not saying that we are head and shoulders better, but we are at the top in terms of dockage. Some other operators are the same, but I have not seen any better. These machines will do it, it just takes a bit of knowledge some time.