My thoughts are that nobody has the correct answer for this. Two sides to the issue:
1. According to the rules, stop the clock when the ball becomes dead and clock should be stopped.
2. Because the clock operator is so far from the action it is sometime difficult for him to know if he should kill the clock so sometimes he must wait for a signal.
3. Officials are taught to have SLOW whistles. IW's are a terrible nightmare. However the time difference between a slow whistle and the time the ball actually becomes dead could be as much as a second.
I don't think we will ever have a definite answer until someone issues an official ruling on this.