Interesting gauge....

Note the small gauge at the bottom. It has the symbol of "pressing down at the 5th wheel" in it, and reading about 60 PSI

 

62 psi was about 34,000 on the Freightliners I have driven.

Just scale like you normally would, take a look at it if you're close to 34k on drives.

 

34000 was about 61 psi on the Cascadia I use to drive. Get a heavy load and scale it out, take note of where the needle is, also if your sitting up hill or downhill it will effect the readout,,,, 5th wheel was always pretty much in the same place, so not sure on that.

But always get a scale ticket, for the last bunch of loads I did in the Cascadia I almost never reweighed, managed on a few occasions to guess the hole correctly on a 79k+ load