With my summer Pirelli Scorpion tires I get, according to the app, around 22-25 mpg on a Defender 90X. I live up at 7,000' so my engine runs leaner due to atmosphere. It also gets better when I remove the roof rack. The more you put on top the worse milage it gets. My snow/offroad tires also shave off a couple mpg.

My point exactly. I was looking for an actual explanation to what exactly that App "Efficiency" means and how it is calculated since IMO it is way "off" to be only pure mpgs.

I am well aware that off-road tires and lifts add weight and reduce mpgs and I am fine with that. Not complaining at all, I was just adding my own experience here. I'd rather have the heavy KO2s navigating sharp rocks in the trails than do 23 mpgs with the stock tires and sit with a ripped tire on the side of the trail.

We've had our P400 since 2020 and I was looking forward to it getting better mileage than our 5.0l LR4, it does not get better mileage than the LR4, nor is the rear cargo area as large, nor are the third row seats as usable. All that being said, we love this car, nothing against the LR4, but other than those few nit picks, this car is better in every way and is by far my favorite vehicle (that's saying a lot, as I had a Mitsubishi Lancer Evo addiction for several years and still miss the race track at times)

I have a 2023 D90 P400 and according to it I am getting 17.7 to 17.9 city, havent been on the hwy yet so I don't know what that might get...