[jcunning]

The compression looks pretty good.
I would do a leakdown test and see what happens. If you get a lot of leakage into the crankcase, then I would suspect the rings never seated.

The next possibility is that the valve guides are leaking oil into the cylinder. To have all six plugs look exactly the same means all cylinders have the same issue and I think 6-12 bad valve guides is unlikely, but not impossible.

Most of the "breaking in" is done in the first 100 miles, so I would start some diagnosis to try and find the problem.

My personal guess is that the rings never seated right. Oil is not being scrapped from the cylinder walls and is being burned up.

You posted: "JE oil ring gap says 0,015", I'm at 0,0138"
This seems like you are below the minimum and could be the issue. The top ring could be binding in the bore.

Further down you say the gap is .15mm. I really hope this is a mis-type as this is way below the minimum gap needed. 0.016" = 0.4mm

I recently went through a similar disaster with a 4 cylinder turbo engine. I was burning 1 qt every 500 miles. I made a few mistakes that caused my rings to not seat. I redid the engine again and fixed all my mistakes from before and now it doesn't burn any oil after 1000 miles.