I have a 6620. This year the beans are really dry. They look thick enough to be making 50-60 boa. Not mine hopefully I can get 40. Concave is at 17. Speed of 390. Air at 870. Chaff and seive set at 1/2 inch. Straw walkers show good thrash, no beans there about 2 or 3 splits per handful from the grain tank. 1.9 mph. Am I grinding the beans internally somewhere? Thanks for your advise.