Well...the Order are really low on numbers. That's a reason they could give out missions to Mercenaries. Seriously, the Order would be wrecked if the Core wouldn't be there to pop some Nomads along the way.
Don't get me wrong, The Order are my favorite when talking about the Omicrons, but since the loss of Toledo they can barely survive an attack from the Nomads. It wouldn't hurt them to give a bunch of credits to Mercenaries and let them clean out some of the Nomads. In Mu it wouldn't make any sense, though...as far as I know, access to anyone who isn't an Order agent is restricted.