My experience is the calling of stalling changes as we get into regionals and state.
Suddenly- warnings abound - but during the year, you have to be running away from the guy to get a stalling call or the officail waits until the last 2 seconds of the match with the first warning.
Call it quick and make it stick. All year long.
Heavy Heights - OMG It has come down to who ever wins the toss gets the win in the last OT. Call them both for stalling and put a fire to their feet to make some offense.