Dude... the rules weren't changed. They were just never finalized before. The committee was simply voting on the final way the delegates would be divided up.
Of course, the rules were changed. Changing the rules is changing the rules, even if they were subject to revision for whatever reason. Only in banana republics are the rules changed after an election has taken place. In republics, the rules are "finalized" before election day, not after.
The question boils down to this: if Santorum had won, would the current rules had been "finalized?" I think that would have been the case. Romney win 2-0; Santorum win 1-1. That's how banana republics decide elections.
Except that it was "finalized" before the election rather than after, no?