fuel usage

First of all: I love this game, really enjoy the return of the endurance races.

But while racing these events I noticed that the fuel usage is not the same as the cars in real life.
The Audi R18 can only do 4½ laps on Le Mans, that’s less than 20 minutes!!! The Peugeot 908 can do 7 laps, much more than the Audi (?!) but nowhere near the +/- 45 minutes that is a stint.

Also every car I checked had 20 (liters/gallons?) as the max when it’s full.

Anyone knows if this is deliberately done to force people making extra pitstops or is this a bug in the game?

What annoys me too is that the fuel indicator is so tiny (if you use a view outside of the car)