Thank you very much for your answers.
I think i will do also the second oil change on 7.500 km just to feel better.
I changed anyway oil on all my bikes on 6-7000km intervals oil.
As for that high oil consumption that some report... sounds weird to me. An engine that mentions to its manual oil change every 15.000km, should not burn 200-300ml of oil every 1.000 km. Its unacceptable !
Thats the oil a 2 stroker needs. At least my 1 cylinder XR400 needed less oil than that.
Of course, i bet that KTM says that this oil is within tolerance...