Wattage in US vs AU/EU household appliances
Good question.

The US model has to have its power limited to the maximum that can be delivered by a standard power socket which is 15 A at 120 V which is 1800 W.

The Australian's have the advantage of higher voltage and can use higher power and get the food ready more quickly. According to Wikipedia Australian sockets are 230 V, 10 A so that gives a maximum power of 2300 W. (The cooker is pushing it a bit at 2400 W.)

The manufacturers either limit the power by special build or by software control.