So I might have requested the refund too soon. You are saying that KVM only connects to up to 9 KMs which cost $20 each and KVM Pro connects to 9 other KVMs. Is that correct?
Eight Secondaries (the 9 includes the Primary), yes.
Much of what you are asking depends on how you are connecting, KVM (remote to another PC) or Seamless (you can see the Secondary's monitors).
KVM Seamless = 9 (Primary + 8 Secondaries).
KVM Remote = 1 concurrent remote connection.
KVM Pro Seamless = 9 (Primary + 8 Secondaries).
KVM Pro Remote = 8 concurrent remote connections.
Again, one Primary per license.
Stardock Support Manager