right. The power level indicated is voltage across some assumed load. Depending on the amp, its calculated to 4 or 8 ohms. When you set these on a Phase Linear at least, you set it to a specific output voltage with no load. That voltage / 8 ohms = 350w. That doesn't take into account meter response at different frequencies, different impedance, or impedance swings in the speaker system at different frequencies. It just makes the meter (or LEDs on mine) dance.