On inductive loads Watts does not equal Volts times Amps, an inductive load is like a motor or ballast that draws varying rates of power based on load, an incandescent bulb is a static load and this is where W=V*A. For Inductive loads W=V*A*pF. pF is the power factor and has to do with the surface area of the wave form and the efficiency of the draw. We use VA to give something relative to the Watts most people think of, the true wattage is slightly lower when pF is factored in.