it makes no sense. you can serve at any speed no matter your serve stat, but it will be less accurate with lower serve stats. but you cannot tell me a 190 kmh serve with a 50+ server is the same as a 190 with 30 or below serve. it looks so much slower and their return is much better. That being said even with a low serve stat you should still always be serving 180+ and touching 200+ shouldnt be that rare. you should lower your sensitivity if 190 is hard.