Interesting to know, but presumably it doesn't change the main point, which is that a digitally controlled system presumably still shoots out the same maximum amount of heat per second as the analog dial controlled system can do. Like a house window air conditioner has 2 states: creating the maximum amount of cold air per second that it's able to do, and off. The digital control on the AC is simply a thermostat that tells it when to turn the cooling on or off. I presume the digitally controlled car heater works the same way, when the ambient temperature is much colder than the thermostat is set to, then it will put out the maximum amount of heat per second that it's able to produce, which is the same amount as the analog slider system can produce.