Why does the refuelling process stop before reaching the chosen maximum amount even though the tank is not yet full?

Certain fuel stations stop the refuelling process just before the chosen maximum amount has been completely reached (for example: you choose the maximum amount of CHF 80 that is reserved in your TWINT credit, but refuelling stops at CHF 79).

This is a safety mechanism as some pump systems still have a little fuel left in the hose even after refuelling has been stopped. To prevent the need for a subsequent payment, the refuelling process therefore stops just before the full amount is reached.

Of course, you are only charged for the effective amount. You can find the amount effectively paid in the statement entries right after refuelling.