I have 205K on my 09 XT. It began slowly using oil about a year ago. Got to the point I was adding about a quart every 4K. Began scratching my chin and getting a little concerned. At the suggestion of my local Subaru service dept. I changed out the PCV valve and ran a can of Subaru oil system cleaner through.....and wallah, no more oil consumption between changes. May not be your problem, maybe it will help. Good luck! Hope things work out.
09 DGM FXT LTD