There is no such thing as KW/h. The charge in the battery is measured in KWh (and your mileage in KWh/mile), so KWh/h is simply KW (the h/h cancels out to just 1). The KW you see when charging is the number you are looking for - tells you exactly how many KWh you will would pump into the battery in one hour if the charge rate would not change (but it will go down as the battery gets filled up, the same as rated_miles/h, not way you will sustain 496 miles/h for a full hour).
Max charging rate for the Model 3 Is 250 kW. Max rate for the Model S is 200 kW. As @whitex points out, charging at a constant 200 kW for one hour provides 200 kW-h of energy, or 100 kW-h in 30 minutes.
Since kW is a rate, talk of kW/h, or kW per hour, is just nonsense.