Sealer section in Skool course

Is this an error? Water making the paper produce shallower scratches should make it act like a higher/finer grit, right? Yet the bullets below seem to say the opposite. If water makes the paper produce shallower scratches shouldn’t wet 400 product shallower scratches more like dry 600? Am I reading it wrong?

Water lubricates the paper and produces shallower scratches than dry sanding at the same grit. Wet P600 lands in roughly the same place as dry P400.