I got the info on Twitter as well. A virtually instant response from them. Now, that's what I call support!
I also asked about Blitz to make sure PAL territories would be getting it around the same time and they said it would be released worldwide on the same day.
I guess that's where we need to raise the issue of missing/disappearing DLC.
Still, I think Harmonix could/should get someone to check that their content is being added each and every week on all of the consoles. They wouldn't need to check each and every country, just checking the US and UK stores should let them know that yep, the content was added and everyone will be happy. It would take mere minutes to do, and help to avoid situations like this.