It seems that iTunes Australia is rather inconsistent when it comes to releasing Volumes of Lab Rats and Mighty Med.
The releases are stop and go, they make some available, then there's an extended hiatus before the next batch are made available.
I was expecting the next volume of Season 3 of Lab Rats, after You Posted What?!? to be released two weeks ago, but it still hasn't happened.
Mighty Med has been on hiatus even longer, they still haven't gotten to the second season at all!
I am especially looking forward to seeing Lab Rats vs. Mighty Med, but as that is season 4 of Lab Rats, I guess that episode is a long time coming.
I did make some enquiries and it turns out that the tv stations in my country won't let iTunes release the episodes of shows they are currently screening, most likely to force the viewers to watch them on the tv instead.
But since I don't watch television anyway, all this achieves is to stop me seeing the episodes at all!
And it's not just Lab Rats or Mighty Med that is slowed down, there are many other shows I cannot obtain that are freely available in other regions.