Agemixer(10:23:49)
Sure the c64 counter chips allow it flexible with an accuracy of 1 microseconds, but the demos and games usually are made in a way they only allow vblank timed (there, 50fps)
Agemixer(10:19:08)
usually there's a setting of speed of 3 or 2 and rarely they use a between-value of 5 i guess. Still, the funkbeat capable routines allow it like every second beat plays 6 frames and even beats do 5 frames, then it is between those (say, (120+150)/2 BPM)