The window a burst technique holds
Jitter clicking runs on arm tension, and tension decays fast. Plenty of people reach 600 CPM across five seconds and cannot stay within a hundred of it across thirty, which is exactly why the five-second interval is reported separately rather than folded into a longer average.
A five-second reading is the honest way to state what a burst method is worth. It is short enough to be repeatable and long enough that a lucky press cannot carry the result.