LOL @ 1kw PSU for that system... OVERKILL! Could have saved yourself $150 buying something more appropriate!
Anyway, that PSU is server grade stuff so I highly highly doubt its the PSU giving actual low readings. Like Thideras mentioned your PC likely wouldnt work if it was reading that low.
If you dont own a Digital MultiMeter, try DL evererst and see if that is reporting any better.