Default [Q] Play store Movies in 5.1 in the U.S.A but not other countries?

Wasn't sure where else to put this but here goes:

Hello all

I currently live in Australia and have noticed that all movies in the play store are in stereo. Doesn't make a difference whether it's HD, SD, rented or bought.

Even movies that are available overseas that are in 5.1 are only available in stereo here.

For example Prometheus in the US play store is available as 5.1 whereas in Australia it is only available in stereo.

The only exception I've noticed is in 5.1 surround is "Transformers the Dark Side of the Moon" which came free with my Nexus 7. If I look in my purchased movies it shows it as 5.1 and plays back in surround sound via my Chromecast. However if you search for it in the play store it's only available in stereo.

Any one in other countries notice this? Any ideas folks?