Let's keep in mind the fact that the tour gross from "31 shows" isn't really giving an accurate representation of average gross per show. Most of the Asian + Australian leg were Arena shows, whereas Europe is almost exclusively stadiums which are bound to gross much more with fewer dates.
Also consider the fact that Gaga chose to do arenas in Australia not because she couldn't sell out Stadiums (as evidenced by 5 sold out arena shows in Melbourne), but because she wanted to keep the atmosphere of the show as intimate as possible. So with all considered, these are some amazing numbers