Balance Thermosats

Stockholm

I have two heatpumps, air-to-air and air-to-water . Using one "Smart AC control" and six "Smart Radiator Thermostat". I want to use the "Balance" function to lower my cost. WHY does it work only with air-to-air? If tado lowers the heat for air-to-air, then the radiator thermostats will work harder, it will not save me money.