Does anyone remember when this sort of consumption was considered normal for a car engine? I don't, but then I'm only just into my forties.
The oil will be going out through one of three ways...
1) past the piston rings
2) down the valve stems
3) via crankcase leaks
All of which are unacceptable in any modern engine. If a car engine use 1 litre in 10 hours, it would be considered dead so why should this be considered acceptable in an aero engine?