1) Although a lower temperature suggests that the drive wastes less energy, I can't see how it means the drive uses less power. Surely the power depends mainly on the motor, i.e. how much it takes to spin up to speed and how long it has to run for.
2) In that picture with the 1A hard drives. That seems quick high, so maybe it means that the power supply should be able to source that current if needed, but i doubt it runs at that the whole time.
Just my 2 cents