Exactly, hence why some people adjust the temp. They want a few mins at hotter or colder than is usually set.If your car is below the set point and you have a 2kW heater it’s going to warm to set point at max power. There’s no magic ‘overboost’ etc.
E.g. if it’s 32c outside a driver might want 10 mins set at ‘low’ to cool down quickly at a lower temp, then maintain a steady 18c for the rest of the time.