Hole in the story

In Jo Nesbø's Harry Hole detective novels, Harry lives in Sofies Gate in Oslo - number 5 or number 8, depending on which book you read. You'd think for a novelist who has to get the details right that this wouldn't have happened... must have been a reason. At number 5 one occupier has put the fictional detective's name on the buzzer - again, the reason eludes me. So here's the buzzer, the front of number 5, the front of number 8, and a view of the street with both buildings in it.
I'd never read the Harry Hole books until I bought them for my father, and they're not bad. It's always intriguing to read books set where you live.