It is NOT unusual for the M112s to burn oil in between changes...there was a class action lawsuit for excessive oil consumption and sluge buildup in these engines after following FSS recommendations with mineral oil. This is probably the moisture condensation issue, but I might recommend taking the vehicle to the dealer...mention the consumption, gunk, and the class action lawsuit and see what they saw. FYI: I believe your engine is guaranteed until 150,000 miles or 10 years as a part of the suit.