It's more than that- LEGO sets are more expensive in Australia, even after conversion, and TLG does it on purpose. Australia's toy market sees LEGO as a high-end toy, and as such, TLG can charge a premium price as a premium product. So they do. In America and, to a lesser-extent, Europe, LEGO does not have this same "premium, high-end" perception in the toy market. Ergo, lower prices.