Jason,
We see no real problem and the dealer would have had to hook up diagnostic equipment to the engine in order to verify set up.
It is a very simple process of forward advancing the throttle, and there is no real other factory set up. Just check out.
The cables might have been off some, though that would have caused either hard shifting, or an idle issue, or no full throttle. We really can’t think it to be that complex. And we appreciate the local Merc dealership helping you out.
The oil consumption is probably fine as there is an alarm on the pump and the upper reservoir.
The lower tank is your main reservoir, the supply comes from the upper tank.
The level you mention sounds light on oil burn. You are going to burn a 50 to 1 mix on an XR-6 engine. So at mid range the ration is up some.
In a mid range condition and not full throttle, you should be able to burn about 200 gallons on a full reservoir of oil.
BCB