I've been trying to hit notes very early, and haven't been able to hit the bad window (not "miss") a single time, despite it being vary easy when pressing late. That'd be a pretty big problem considering the entire game rides on a slightly early window where exactly on beat mostly results in either a "good" or "bad" timing
The whole time i was wondering why i was missing notes, and i think that's one of the main reasons. You're forced to hit notes slightly early to get Sick timing, but the only leeway is a really small good window and zero bad window, that or it's frame perfect.