In many of Tesla's videos about the model S of the years they talk about the car learning when to pre heat the cabin.
Im not sure if this feature is in the car yet, but is it possible these cars are warming up to be driven at a certain time, day after day while being parked. And is it possible that if the cabin doesn't do this yet, that the battery pack is? Maybe the battery pack has two stand by temperutre settings, warm enough to not harm while driving (never goes below this one), and warmer to give more optimum range. Both of these temps below optimum regen.
So at the airport the car might be trying to maintain 32°, and then each day at 8am and 5 pm it brings the battery pack up to 50° expecting to go do a drive?
also its next to impossible in measure SOC. the computer is working crazy algorithms and past performance to guess the SOC. This is why so much range and usage information is available to the driver, this information is already needed for SOC calculations. The tempeture drops plus sitting around for Long periods would have major effects on estimates, hence while range is coming back once driven and faster then expected when charged.