Split times are the recorded times between each shot fired on a shot timer. A shot timer starts with an audible beep, as the clock starts, then each shot fired is recorded. When the shot timer is viewed or rewound, the split times are known as the time between each shot, after the initial draw first shot time.
Guesing at a time, or using a stopwatch, is just a ballpark estimate. The point here is that a wheelgun split times are controlled by the speed of the shooters trigger finger and the weight of the spinning cylinder. I really, really doubt that this auto revolver is faster than a conventional K frame S&W revolver.