In my car, oil consumption is below normal. There are no errors. The check is off. I know that if you block the tube that goes from the oil nozzles to the inlet, then the oil consumption will increase. Can this be done? did someone do that?

 

The correct way to do this is to premix or to increase the injection rate in the ECU. I'm not sure what effect blocking the vacuum lines will have, but there is already a check valve in there, so I don't know where you're getting that idea.
What is your consumption rate that you consider below normal? It varies quite a bit with driving style.

 

I drove about 2000 km. during this time, the oil level on the dipstick has changed no more than 1-2 mm.
Premix in what ratio will help in my case?

 

I've seen similar oil consumption with driving too easy back when I had a new 8. Try and change driving style and see if it changes. Add some pre-mix as an added safeguard first.