The stats reset with a full charge (0 electric miles / 0 kWh Used). If you use remote start to precondition after the car is fully recharged, the car may use some of that power, which is then replaced from the grid if the car remains plugged in. If you can’t wait for that to happen, or if you're not still plugged into the grid, the computer still recognizes the car has been fully recharged, and some of that power has now been used for the preconditioning. For energy use accounting purposes, you’re merely using power for non-driving purposes before you start driving instead of later in the day’s travels. Any power used for heating, cooling, accessories, or battery maintenance reduces the amount of power in a full charge that can be used as fuel by the electric traction motor for driving.
If you don’t reset the display, then drive until your Gen 2 battery is depleted and the ICE comes on, the display might read X electric miles, ~14.4 kWh Used. If you could reset it, at day's end the display might read the same X electric miles, but only ~13.4 kWh Used if the preconditioning already used 1.0 kWh of that full charge power. Would you then think you got "better mileage" because you drove X electric miles on 13.4 kWh Used instead of 14.4, or would you wonder why your kWh Used number stopped at 13.4 when you normally get 14.4?