I never use DEFROST since I live in a desert. However, I almost always see 4.5 KW draw on the heater in ECO or D. This is because of my short (3-5 mi) trips. Eventually, the car reaches the setpoint temp and then dials back the heater. Of course all of this depends on the outside temp and air speed. On my rare longer trips, I do see a difference between ECO and D. The best way to observe this is drive with cruise control on and then switch back and forth between ECO and D.