See... there's more to a vehicle conversion than simply swapping the steering gear to the other side!
Going by that pictorial display, the US version's auto fluids are "exchanging heat" in the coolest section of the radiator whereas, the Oz variant is trying to "exchange heat" in the hottest section surrounded by the engine coolant straight out of a hot motor... that's been well though out eh?
In a nut shell... if the coolant surrounding the transmission oil "heat exchanger" is at a higher temperature there can be NO reduction in transmission oil temperature, thus an external aftermarket transmission cooler should be considered a "must have" item for a vehicle getting lots of use in a multitude of weather/driving conditions, the ONLY benefit I can see with this configuration is a quicker warm up period for the transmission