To me no method is wrong, but I like the valorant one more actually as you can track your aim discipline and assess crosshair placement, whereas in CS it's a bit irrelevant with rifles (you can't tell if you have improved just based on data, like you could be spraying like crazy and just getting a bit lucky and end up with an 80% hs game and then wonder why u fell off when ur stats get worse, even though you could have gotten better in reality)
I think if the calculations were done the same way CS pros would actually end up under val players as spraying is more rewarding in CS . (Check out what a d0nk peek is and tell me that game is not balanced for spraying xdd).