I expect that is the total input power rating of all the power supplies for everything: laser, steppers, controllers, whatever. Add 'em all up, round upward to the next highest multiple of 10 W, and there you go.
It’s not exactly dishonest, but it inspires zero confidence for any of the other “specifications” they might list.
One useful byproduct: maybe the better manufacturers will include power supplies with enough capacity to handle the actual loads. It could happen!