Don't know if fitted, but have witnessed before on same type, the pilot pays little to no attention to the fuel gauge and concentrates on the fuel computer ( I would believe which ever one is less ). How accurate is the fuel computer? How accurate are the numbers entered? It might under read a bit or over read a bit which adds up over a few weeks if you are just entering fuel added. If it is under reading , unless you fill tanks full, you will never know until it goes very quiet.
That aircraft type is tricky to physically check a part fuel load. If they depart the main bases with full fuel, it is easy to do a daily check of the computer and gauge when filled again. Possibly their loads limit that.