I think Fastned look at it differently they look a throughput and although faster chargers are more expensive more kWh's are sold per unit of time.The thinking behind higher equivalent per kWh cost for faster charger is simple: if you want speed, you have to pay for it.
What is fast charging? How does it work? How fast can it get? And why is a network of fast charging stations so important for the breakthrough of electric cars? Fastned Head of Network Technology Roland van der Put wrote an introduction to answer these questions.
Also Fastned the story can be read online for more information.