Yaris XP9 diesel 90hp burning oil

[bubu]

I have a 2007 Yaris 1NDTV diesel 1.4 90 hp with ~130.000 km
Story 1
light came up for oil ( lower than minimum)
added 2 L of oil - dissapeared in 1 week ~ 300k

Story 2
made a complete revision at Toyota with original oil
=>maximum oil level
half indicator after ~8000km
added ~800 ml to the engine...
=>maximum oil level

after 2 days(30km) oil level is reduced about one quarter

Note :
I check oil level under the same conditions in the same place.
Turbo was visually checked at least twice there is oil inside but small quantity
no oil under the car also checked twice by Toyota and other service
cooler level looks the same ...
no black or blue smoke
any ideas ?