IMHO I think you're wrong. If you only set the power that goes through the heater, the heater would become more and more hot as long as the power is engaged. Like a regular e-cig in watt mode or an unregulated device like the Milana for exemple. Here the draw strength can play on the heat when taking a hit.
With the TM you set an approximate temps with the dial. The power delivered can fluctuate depending on your draw strength, time etc... The power varies in order to keep the coil a the same temp even though other parameters are changing.
Hope that makes sense ?
You may be right, I am not so familiar with e-cigs etc.
However...
In fact (if I'm not wrong) the current flows directly from the battery, through the top case, then through the heater, down to the electronics board. I'm no expert in electronics, but having seen the internals, this is more or less how it works. Theres no any temperature sensor, airflow sensor or anything like it to stabilize temperature and make it consistent (especially throughout a session, in session mode). So you are still not setting a temperature, but the power that will be delivered to the heater.
And, as you said, it still may be designed so the power to fluctuate in order to keep the temperature at the same (approximate) levels even though other parameters are changing