The dealer charges around $20+ for a litre of Castrol TWS. The Edge is cheaper because it is available in the open consumer market and no need to go through the dealer.
TWS is no longer available in Australia and the dealers are filling up the /// cars with Edge and still charging the same. USA is a lot cheaper for a lot of things given it's a volume market, and unfortunately in Australia for everything we pay a lot. Hence the Edge is expensive compared with the US market even through a normal retailer.
We get ripped off for everything in Australia. Just imagine paying $170+ for a E92 M3 compared with what you pay. Mind the two currencies are on parity these days.
E92 M3 2007 - ///PE with Test Pipes and BPM Stage II; CF Interior & Splitters; CIC with Connected Drive