From the chart titled "Recurrent Auto report showing..." I would guess that the reason for the spread in low-temp mileage has to do with which models have heat pumps.
I have to wonder if the heat pumps are also used as a way to maintain main battery minimum temperature. That would require a liquid heating / cooling loop so might also improve mileage in high ambient temperatures (past 95°F there are 'accelerated side reactions'*; below 59°F there are 'slow kinetics'**).
Also, I would expect the numbers for the Audi e-tron to be very similar to the Porsche Taycan. There doesn't seem to be much if any difference between the two - to the point I suspect a simple re-badging. Anyone been hands-on with both of these?
*so faster battery degradation over the life of the car
**so poor performance