Greatest Hits

So, I was looking at some old records of my dad's and came across the Greatest Hits 1 album but it was different from the official version. On the album, it includes Tie Your Mother Down, Keep yourself alive and under pressure. It also discludes Save Me, Good old-fashioned lover boy, Don't Stop Me Now, Now I'm Here and the Seven Seas Of Rhye.

Does anyone know why this is the case? I am Australian if that helps.

wasn't the Australia release the same as the US release, but with TYMD added?

I can't remember all the details exactly, but years ago I had several copies of GH from different countries, including Canada, Yugoslavia and Bulgaria, and many had varying tracklistings. The Bulgarian one was a double!