The easy way I've found to remember which way this goes (moreheight/less height) is that qnh provided by ATC is always rounded DOWN to the nearest hectopascal.(mb)
The reason is safety. If an aircraft is 30ft too low on approach, the results in a worst case scenario are potentialy more dire than if it's 30ft too high. Rounding the Q down provides up to 30ft MORE actual height/altitude. So, the lower the subscale is set, the higher the aircraft will be.
Try it on the ground. Winding the subscale down will show you at progressively lower altitude.