I see what you mean on the backwards part. I knew that would allow the coverage needed, although I'm still curious on why 800 was picked for up here. I think the comparison between VHF and 800 still favors VHF in the more remote areas, such as around the fringe of county towers. I don't know all the county towers here, but I'm fairly skeptical the existing towers now on 800 can push far enough out to reach the county boundaries for mobile units. Maybe that is where the dual system comes in where mobile units with default to VHF instead of 800 past a certain point?
I'm basing that on the Waupaca SO keeping VHF but going digital and the digital signal not being totally understandable within 5 miles of the county border (where I would respond from.) I haven't paid attention lately, but at the house (about 2 miles from the border) the SO channel would often be too digitally garbled to understand.
Also, if a few now, and probably decently more later, departments opt for a separate 800 local system; is the general aim then to have all agencies statewide standardized on a APX or equivilent dual band radio for interoperability? Or am I not understanding how the links you mention would actually function?