Last trip driving my daughter from Central NJ to college in Ann Arbor MI (August 2021) I got 20.5 MPG on I-80. Hills in western PA hurt, flatlands of those parts of OH and MI help. Contrast when I picked her up when school closed ~Thanksgiving 2020 due to the pandemic, when I got maybe 17.5 MPG returning home. One would think that cold weather would enhance turbo (though no turbo involved at steady highway speeds) and just provide more dense air in general =more O2. Believe the culprit is the oxygenated fuel forced on us in "winter". My mileage is consistently better by 2-3 MPG on summer gas.
I track every gallon I burn and hand calculate. I've noticed that the summer blend averages ~2 mpg better. It changed over in about early May. That's not hard evidence, just from what I'm consistently seeing in fuel consumption each year.
Those of you so adamantly against collecting data on real world fuel economy must never take your trucks to remote places (especially based on your locations). To me, understanding my fuel range for mixed driving, highway only, city only, and off roading is critical for long treks into the middle of nowhere. Fuel economy is the driving factor for me having a Raptor, combined with a large fuel tank, to get the most range when I'm 3 hours from the nearest gas station.