My board doesn't follow the manual that is posted everywhere for some reason either. I was trying to get 12.5 bps on 5 flashes but it always felt slower. I found another manual here
that says 10 flashes is 12.5 bps while 5 flashes is 10 bps. This now matches other 12.5bps guns and I have also verified this by recording the sound and counting how many times it fired.