My RS6 drinks like 1 liter oil after 4000 kilometers.
I think its odd and i contact Audi about the issue.
Apparently it is normal... And they claimed they have several RS6 owners who came in after only 2000 kilometers and had to refill (Im not talking about the break-in time of the car now)
It depends alot of how agressie you are on the throttle

I asked at what ooilconsumption levels they replace the engine / fix the problem.
They said that they only do this if the car drinks more then 1 L every 1000km LOL