Plus you have the efficiency to look at. About a 10% loss for the transformer. Magnetic ballasts are a form of step-up/step-down transformer. Put a volt meter and an amp on the wires to the bulb of a hps light and you can watch the voltage go up and amps go down as the bulb warms up.From what I've been studing in school, a stepup isn't going to do anything productive. They don't increase amps, only voltage.