Consumption Cayenne V6 vs. Cayenne S

Hi, my neighbour is a test driver for the Porsche plant Leipzig (no joke) and he compared the Cayenne S with the V6 in terms of consumption, but he wanted to tell me all the serious things that he drove the S with 11 liters on the motorway and the V6 with 15 liters (with the same driving mode, both models switches). I still can’t believe that because that would contradict the laws of physics because 8 cylinders naturally need more fuel than 6 cylinders. Who is both automat I am talking about a cosy, cruising driving style with 120 – 130 km/h cruise on the motorway and a maximum of 60 km/h in the city without traffic lights. What are realistic consumption values for the V6 and S (both automatic)?