Do I still pay if I drive a lot of km (more then 18.000) in a year?

The minimum fixed monthly premium is always due, month after month. 

But if a Commercial Offer is in force and you have already paid for 18,000 km, all subsequent mileage adjustments at the end of the month will be ZERO up to the Commercial Offer expiration. In this case you won’t pay more than 18,000 km per year.