2.0 T.S. and the oil consumption…

Hi, I’ve been using the 147er as 2 liters since 2 weeks now, now after approx. 1000 km I have found an oil consumption of approx. 0.3 liters, which in itself should not be dramatic since the workshop master told me that up to 0.5 liters are ok on 2000 km. my actual question is, why does this engine actually consume oil? where with other engines sometimes garkein consumption can be detected. is the engine designed so that oil is inevitably consumed, or why is it? toni