settings and loss

I'm an "emergency replacement" 9660 STS combine operator. I could use some help in getting the machine set with minimal grain loss. I was in some 22% corn yielding around 180 bu/A (893 corn head running about 4.2 mph). The loss monitor was showing next to no loss. When I got into 18% corn (aprox same yield, speed and settings) the monitor showed a fair amt of loss. >>3-4 bars on both shoe and separator. What happens with the drier corn and stalks?...and what adjustments should I try? I guess I just don't thoroughly understand the process yet.

Thanks for any help