Today I spoke with the dealer and he explained me like this:
He put a 2015 model crankshaft, bearings and parts instead of the 2013 model.
This should be so much better quality that this engine it will keep running good for much longer time.
Beacuse these parts are a very tight fit, a 125cc will show much less power while breaking in.
He convinced me to continue breaking in and gave me lifelong guarantee on the repair.
He is not that old so I guess I can trust things will work out one way or the other.
Lets's hope for the best.
I will get back at this topic in februari/march when I am back in holland. Then I'll be completing the 10hour brake-in.