I can only conclude those temperatures must be colder than we've experienced thus far. I believe my last car's seats and steering wheel heat activated at temperatures below 40F.The remote starting system also activates the climate control (if equipped), the heated seats (if equipped), and the heated steering wheel (if equipped), depending on temperatures outside and inside of the vehicle.
My experience is consistent with yours.I've auto started when the car read the outside temperature outside as 30°F and have not had the heated seats or steering wheel come on. I did find out the other week that after shutting the car off with heated seats and steering wheel on, pumping gas, and returning to the car, the heated seats and steering wheel came back on automatically. However on the same trip, I stopped at the grocery store for about 15 minutes, turning the car off with heated seats and steering wheel enabled, and when I returned they did not turn back on automatically. I'm curious as to what the temperature and time thresholds are to have this auto enable.