Hi there,
I am a swiss Suburban 07 owner and I experienced some surprisingly change on my oil consumption after some minor changes I did myself.
As I dont know which is responsible for the change I will list the Reasons why it might stop to consumpting much oil.

1. I start using 5w30 standard oil (because we dont know what the preowner was using)
2. Installed an OBD2 Chiptuning for 120$ what gives an much better response on throttle controle
3. Installed an Spectre cold air intake
4. driving on switzerlands mountain roads and no more in New York City

hope someone can benefit from my experience