3 or 4? digit is to adjust the speed/odometer.
Thank you, this was a huge help. My dealer didn't know this either, now we both know

For people that look at this the default values are:
Cforce 800 = 529
Cforce 500HO = 705
The other screen "L16H" I just figured out, it's for "LIGHt". This is the screen that lets you adjust the light level or brightness of the dash. This isn't in the owner's or service manual.