qfcsm,
I am of the understanding that the answer to your question of "WHY?" is that QF and the FAAA went to the AIRC in an attempt to resolve their differences.
The AIRC most likely told them both to pull their finger out (though they probably said it a little more eloquently than I did) and come to an agreement expeditiously (sp?).
Therefore, it is no wonder that after much angst and chagrin that the FAAA came out with an agreement that they suddenly endorsed. Basically, because they HAD to.
With the government re-elected, the industrial laws are going to go through a significant change. Unions will have even less power than they do now, which means that striking will become a thing of the past.
My thoughts.
SG