Except, a pressure gage reads the number it's pointing at. Not 1 hand means the number it's pointing at and the other means 5 times the most recent digit passed plus 1 for each tick mark.

I'd wager that most people would never even see a pressure gage with two hands. Dual-indicating double-bourdon tube differential pressure gages are quite rare in the real world. Usually for that kind of application you'd go digital.