In counting the bass riff rotations, sometimes its 6, sometimes 5, sometimes 7 etc...
But it's not necessarily "sometimes" ...it's probably
at specific times, right? E.g., it's 6 times before the first chorus, but then 5 times before the 2nd chorus, and then 7 times before the 3rd chorus, something like that, no? (I have not listened to that tune in ages so I'm just giving an example.)
So whatever that pattern/roadmap is, it becomes
everyone in the band's responsibility to learn it that way and to know when to go to the chorus. If the lyrics are the same in every performance, they can be used as an obvious audible cue.
Or, perhaps someone in the band is "conducting" via visual cues; e.g., Whenever Prince Puts His Right Hand On His Ass, Go To The Chorus. Again, it becomes
everyone in the band's responsibility to keep an eye on the conductor and follow the cues.
So no need to count or to use charts; everyone just has to learn their part and be responsible for understanding the form.