ISX is also free to amend it however many times they like.
So what do you mean by the ASX having fought the amended SOC tooth and nail???? The SOC has never reached court. The only concern the ASX had initially was that the amendment would be redundant and would only serve to delay. It was concerned that ISX may not have the cash to fight the battle.
Every time ISX amends its SOC, the court date will have to be pushed back in order to give time for the ASX to prepare its defence.