Kill-A-Watt should read something along the lines of the 615W and will also check the power factor and Amps.
For comparison, when I build custom lamps customers can get ~300 PAR W for $1500 and double the efficiency. If they build it themselves they could probably get 500 PAR W for $1500. So they way I look at it, generic LEDs/epileds are not suitable for grow lamps, half baked engineering. Harsh I know, but I believe you would be much better off using the HIDs.