2012 LR4 Gas Milage Increase, What could explain this?

I had some issues with the LR4, this is a car I bought when my Full Size RR was in the shop and held up due to COVID. So, I had numerous issues and mostly revolving around head gasket and subsequent parts deterioting on the coolant system. (Thermostat Melt Failure, that little insert that awkwardly sticks into the water pump body, the vent screws failing, water hoses failing etc.) Took it for the last of twenty test drives after numerous drive way A OK test beckoned road tests and everything held. So I drove it for thirty plus miles and set the trip A to zero in order to track distance. Well then to my surprise, my MPG was reading 24, 24 MPG,never had I seen that and prefer the Cayenne S over this car for road trips as the Cayenne gets 22 MPG on average. Here belpow I show my trip B which of course includes trip A and then the trip A post repairs. Any ideas?

What did I possibly do???

22.2 average mpg could be possible if you recently reset the trip odometer and driver super conservatively. Once you start packing on like 5,10,50,100 miles that should tank to 11-13mpg....if you're getting 22.2 after many many miles of driving and haven't reset the trip odometer then I honestly would think the computer is overly generous haha...22 mpg is kinda unbelievable!

I got a reported 24 on my way from Bend to Oregon City on my way back to Portland, but that was overall downhill, at a very steady 60MPH, following my buddy towing a trailer. It dropped very quickly from that once I reached city traffic. It also reads high by a few MPG from what I calculate based on distance/gallons when I fill (haven't figured out how to calibrate it via IID Tool yet)

The reading is optimistic. Roughly 8-10%. I’ve calibrated mine with my IID tool and it’s almost spot on now.

So I wouldn’t get your hopes up too much as far as being that economical. Check distance and gallons used at the pump.

The initial measurement was on a round trip. So the up and downs / elevation start to finish were relatively equal. It was around town and it was without the AC on. Since then, it has continued to get over 20 MPG at around town usage and at 70 MPH speed. I am planning on checking the odometer against Highway Markers and then check true usage. But there is no reason to think that something changed in accuracy based upon the repair work. But, it could be.

It just seemed weird.

Here is a screen grab of my mpg history and last few fill-ups. I can tell a big difference in trips that involve flat places like Alabama, Florida, Oklahoma. Sept 9-12 below was a trip from Nashville to Tulsa pulling about 80-85 mph steady. I’m sure doing 70-75 would help mpg a little. Around town I get 14-15 mpg almost exclusively city driving