Motorhome fuel gauges

[TEO]

What's with the fuel gauges in motorhomes?
I had an '88 Southwind for a number of years and the gauge baffled me. After filling up, the needle would be pegged on full until I put over a hundred miles on it. By trial and error, I found that I still had a lot of mileage left when the gauge read "Empty", so I got in the habit of refueling at least every 400 miles. Then I had a Safari, where the needel would stay on "Full" until I drove over 300 miles. Unlike the Southwind, when the gauge said "Empty" it really was empty and I don't want to discuss how I found that out.

Now I have the new (to me) 2002 Journey. The dealer "Claimed" that all fluids were full, but you never know. This week we ran it to the point where it was down to 3/4 full. I wondered how full it really was from the dealer so I filled up this morning. It took 22 gallons of diesel and I can assure you that when I was done it was really full. Can this be right? Can the fuel gauge really be accurate? Amazing!!!

Paul