I am a Yacht capatain and have run may yachts with various fuel consumption gages/meters both on the main diesels engines and the gas engines on the tenders. I my experience over the years the diesel ones usually start reading inaccurately after a year or so due to the small partials of algae etc. getting in the flow sensors and the gas ones usually work quite well. I figure due to the marine environment and marine fuel tanks usually being in the engine room (hot air surrounding them and colder water underneath them outside the hull) plus many marinas don't maintain their tanks as well as highway stations lead to early failure.
I would ASSUME and we all know what that means; highway road use would be kinder to the meters and they would probably perform well.
Chuck
Chuck & Katrina
2000 Featherlite
H3-45 Double slide
2014 Jeep Grand Cherokee Diesel