Try searching this forum for 350SDL, oil consumption, and whatever else you can think of that relates, like engine family, whatever it is.
There were some good posts on this engine a few months ago. Until that time, I didn't know that there were problems with it. This doesn't mean that everyone has had problems with this engine.
From your cylinder test, I'm led to wonder about valve stem seal problems. However, I've never done leakdown tests, so I'm not sure how to relate these. I do know that for the oil consumption problem in a diesel to be related to the lower end, the compression typically is very low. Your compression readings are good. I've always only been able to do a compression test. If I ignore the leakdown numbers as if I never saw them, my reaction is that the oil consumption problem is in the top.
How does the engine run?
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in