Filling. How much intermeddle.

I tucked myself just now a full tank. I drove to the gas station, when the light bulb is not burned, but the arrow has reached (not climbed) on the red indicator zone. Filling out 66 liters. I was surprised. The next day, I made a request to the official dealer from whom he took the car. The first thing that wanted to know is the amount of fuel in the tank, in which the light comes on. ML said that 8 liters. Just found out the size of the fuel tank on models that we sell -. 70 liters
Next started calculating. If the bulb is not burned and was even a small margin, then 10 liters more left in the tank. Refueling was to "otschёlkivaniya" pistol. Without topping up under the neck
A question in the following -. Or not cheated at the gas station

?