Hey CCC, I'm wondering the same thing.
I submitted my application for QD MEL and SYD bases last week and got the email saying they "are reviewing the application and will be in contact shortly", so I guess that means an email whether I do or don't have an invite to the Assessment Centres. But seeing as the SYD ACs are in just a few days time, it is cutting it a little fine with not a lot of notice for us, one way or another.
Guess that's exactly why you need to be 'flexible' in this job!