That table is wrong because it lists the entire power consumption of the system.
Come on, think. A 6950 has 2x 75w power connectors. And it draws a max of 75W from the pci-e slot.
That comes to a total of 225 watts. There is no way it can *physically* go above that.
a 1200 watt could run 4 6950's, but youd be operating at close to 100% depending on the rest of your setup
4x 225W = 900W