NFHS calling "play ball" after dead ball

[shipwreck]

Can someone please tell me when the rule changed from umpire calling and signalling to "play ball" after a dead ball situation. A few years ago the rule said when the pitcher has the ball in the 16 foot circle and the umpire says play ball. Now the rule states when the pitcher has the ball on the pitcher's plate, and the umpire says play ball and gives a signal. I don't remember the change but it was the first way on the 2007 test and I know the second way by the 2011 rulebook. Kind of at a loss when it actually changed. Dave