[EricH]

The GDC made a ruling: It's when the clock hits zero. As soon as the clock hits zero, automode is over, no matter if the sounds have sounded or not.

http://forums.usfirst.org/showthread...8840#post28840

If the clock hits zero, and you step forward right afterwards, and you get a penalty for stepping forward before the bell, you might wish to show the linked Q&A to the head ref. Whether the ruling is changed or not in your case, you will get clarification, and possibly an overall change in how it's called at the event.