1. I booked a car for 12 days for the amount of 284,94. 2. With that I got 2.400 free kilometers. In total I drove 2.630 km. The charge per extra km was 0,17 cents/km. Therefore 39,10 in total for the extra driven km's. 3. I returned the car three days earlier than expected. 4. According to Sixt I now owed 368,93. So 84,99 more than the original rental agreement. 5. So I actually ended up paying more for returning the car three days early. Does this makes sense to anybody? It does to Sixt Customer Service and their after sales calculation team.