I recently had to have a new engine installed in my X5 per the beaker ship. I have noticed that my oil level has been slowly creeping lower and lower. It is now showing to be just above half full. I discussed this with the dealership service department and they said that it is normal for the turbos to use some oil. What is everyone else's opinion and is what they are telling me accurate? It doesn't sound right to me, but this is the first turbo engine I've owned..