They are 1200W PSUs, but can provide more power, almost 20% more. 1200W is their safe 80% certified load. In reality you are looking to have 1350~1400W PSU. You can find the datasheet for both of the PSUs in Guy's posts.
Already been discussed a few pages back.
My understanding is the PSUs provide 1200watts output, but 1500watts at the wall.
NO. ~1350-1400W output 1500 at the wall.