I'd agree that the M112 engine should not be burning that much oil. Most likely the rings are sludged and leaking oil past. When encountered at the shop I work for we recommend doing an "engine flush" with a BG product specificaly designed to cut sludge out of engines. Doing this almost always improves oil consumption execept in the worst case scenarios. With the relatively low mileage of your engine, I doubt that you have a "worst case".