Update after just over 4000 miles on our 2020 148” HR cargo van, stock tires and EcoBoost. Indicated (yeah, I know ...) cumulative mileage is 16.6 US mpg. Mostly Highway trips, many Sierra pass crossings at 8000-9000’, some urban, some dirt roads etc. About half of this mileage has been with California winter gas, all 87 octane. I try to limit Highway speed to 65-70 mph but with freeway flow of traffic and EcoBoost HP it’s easy to find myself exceeding 80.