I was assuming they were measuring power consumption when actively playing a game vs if you're just sitting on the dashboard/menus. I'd also like to point out that at least the 360 (and maybe the PS3 can do this too) had a mode where it's "off" but still actively downloading things. There is an option that allows the console to stay on long enough for a download to finish even after you turn it off and then it shuts off when the download completes. I would imagine this uses a different amount of power than other states.
This my be a stupid question, but about the power consumption on consoles, when they say OFF do they mean in stand-by mode? Or OFF OFF as if it was unplugged?