It's more complicated than that. The actual supercharger cabinets (the big white things which look like a fridge and actually do all the work) are capable of handling 135kW (or I guess 145kW now). That's true for the superchargers at both types of sites, "traditional" or "urban". But any one car plugged in on its own will only get 120kW max., or 72kW for the urban style. So, the terminology has bifurcated and people discuss the exact same system in 2 different ways depending on whether they are talking about what the system can actually handle vs. what the car can receive. The point being that the 120kW and 135kW designation is the same thing just from 2 different viewpoints.