Correct, but the time you can stay is surprisingly generous in Oslo, between 3 and 24 hours, depending on location. I used to dread driving to Oslo, but after I discovered that the municipality had repurposed an old bunker to fit hundreads of chargers/parking spost dead in the middle of town, I visit with gleeful joy :P

Here is a map of all charging points provided by the municipality around Oslo: https://experience.arcgis.com/experience/2053e5d9f24c48c487e...