Mr Matt, I'm not sure there are any primary users of our specific channels, at this point.
It looks like the rules were possibly worded in anticipation of assigning some there, in the future
I think RC is the lone group of users of those specific freqs, "right now".

The FCC seems more and more about making money, these days... they're raking in the millions on
each of their frequency "auctions", and they want to keep halving, then quartering, existing channels...
so of course there will be more channels in the future to auction off and license

Good question though...
I'll see what I can dig up if nobody else pops up, who already has proof, one way or another.