mppt vs pwm

I first noticed it when I started using the 230w panel alone, could turn on all the lights, fans and furnace in the trailer without pulling the battery out of float. In the beginning I thought it was the altitude giving my panel superman's cape, but it was the buck converter still doing its job of converting the excess voltage to amps. With the three systems I can run the AC and it pulls more than the 30a the Isc should provide.