Considering 2012-2015 Suburban, have a few questions

Here is the lifetime of our 2011 Yukon Denali XL. The close to 18 MPG fill ups were solo highway. The fill ups below 13 MPG were mostly towing something (either fishing or wake boat).

Put me in the camp of it’s pretty unlikely to consistently get 20 MPG in a Burb sized vehicle. Maybe if you drive 65. But I don’t.

And I also don’t trust the computer calculations. Most (not all) vehicles are inaccurate.