I didnt see it said but with Vickers scoring you can shoot MORE than the 2 required shots. If you see you haven't got a 0 or a 1 take your make up shot.

Craig
IDPA  A50208
SSP Marksman
ESP Marksman
USPSA  A77854

If I notice a hole 1mm away from its intended destination and follow it up with a round .20sec later, it is called exceptional tactical awareness followed by expert marksmanship. If you do it, it is round dumping. FTDR