Ambidextrous Pitcher Rule Change?

[mrm21711]

So about a week ago, 2 guys in our association were working a game with an ambidextrous pitcher. After the game, everybody was confused about the proper rule/interpretation allowing this. I quickly referenced the old PBUC interpretation allowing a pitcher and hitter to switch one time per at-bat. So a few days later, it comes to my attention there was a change in 2009 to OBR:

8.01(f)
A pitcher must indicate visually to the umpire-in-chief, the batter and any runners the hand with which he intends to pitch, which may be done by wearing his glove on the other hand while touching the pitcher's plate. The pitcher is not permitted to pitch with the other hand until the batter is retired, the batter becomes a runner, the inning ends, the batter is substituted for by a pinch-hitter or the pitcher incures an injury. In the event a pitcher switches pitching hands during an at-bat because he has suffered an injury, the pitcher may not, for the reaminder of the game, pitch with the hand from which he has switched. The pitcher shall not be given the opportunity to throw any preparatory pitches after switching pitching hands. Any change of pitching hands must be indicated clearly to the umpire-in-chief.

Anybody know the reason for this change in OBR? Was there no previous rule in OBR covering ambidextrous pitchers and just the PBUC interp? Im just curious as to how/why this was changed. I know the Staten Island minor league team last year had a big controversy with an ambidextrous pitcher but was curious if there were other reasons to simplify OBR.