850's current daytime pattern (with the stick in Crystal Lake) is very tight to the Northwest and Southeast. If some version of this were operating at night, keeping the signal out of Escanaba and virtually all of Ontario (except for the far west) wouldn't be much of a problem. As is....the daytime pattern is designed to protect an 850 in Muskegon, Michigan and an 860 in Milwaukee (along with another 850 in Saint Louis).
The problem is powering down at night would also add protecting KOA into the mix (along with WKNR and perhaps one or two others). The current pattern might accomplish most of that, but the weaker WAIT signal would pretty much get "stomped" by KOA, much as the former WAIT got trashed by WBAP. Moving the stick south would be expensive and probably wouldn't accomplish all that much. That would be true for both 820 and 850.