Careful. Years ago I managed to put a volkswagon beetle to shame with a 1970 ford galaxy 500 with a 390 engine.
The ford had a full tank of fuel and had set overnight in 20 degree weather. The volkswagon also had a full tank of fuel and set overnight in a heated garage of about 70 degrees.
We were going deer hunting in Utah. Early in the morning met at a friends service station. We topped of the fuel tanks as my friend let us have the fuel at his cost then went for breakfast.
Then we drove about 125 miles to a little town just before going up into the mountains. We had lunch then all of us topped off our tanks again. The ambient temperature was near 60 degrees. In the fall Utah can have some very large temperature swings from early morning to mid day.
The ford took about 1 gallon less fuel than the Volkswagon.
You ask why. Simple the Ford had a much larger fuel tank and the fuel expanded from the temperature rise where the Volkswagon had almost no expansion with a smaller tank.
65 miles is not a long enough trip especially if there was any temperature rise from beginning to end.