quattroworld

From that you could estimate how much fuel was used and where the fuel gauge should be.

As an example...
Your gas tank capacity is 20.8 gallons.
In highway driving mode your car should get around 24 miles per gallon.
20.8 x 24 = 500 mile driving range. So 250 miles would be 1/2 a tank just for reference point.
At 200 miles of driving at 24 mpg you should have 0.6 of a tank. So less than 3/4 of a tank but more than 1/2.
I would say your fuel gauge is suspect.
The computer may also error on the safe side to protect the driver.

I drive to visit my son and his family about every month and drive across Michigan. It is almost exactly 200 miles door to door.
The 1987 5KSQ with it's high compression engine leaves 5/8 of a tank of gas at a steady 70 mph and 1/2 a tank of gas going 80~90mph or if I have a stiff headwind. Yep, I got pulled over last year doing 90mph on I-96. Luckily I only got a 5 mph energy ticket with no points. Good for both of us. They got revenue and I can have better insurance rates. I now keep it at a steady 75 mph. I may be in trouble after the Miata engine swap next month 8^)
The 1984 FWD automatic Avant with the low compression engine at 70 mph makes the 200 mile trip with less than a 1/2 tank of gas when I arrive. It is not very efficient. The economy of a 5.0 liter with the power of a 1.6 liter !