An interesting point I notice on the NZ unit is that its max tongue weight is listed as 120kg (265lb).
Having just purchased a second hand OEM towbar in Australia recently, it has a plate on it stating the max tongue weight is 270kg (595lb).
Both the Aus & NZ units are rated at 2.7 tonnes (5,952lb).
Assuming a rule of thumb of 10% load on the towball, this would imply the NZ unit could really only tow 1.2 tonnes (2,646lb), perhaps a little more if you reduce the 10% slightly.
Presumably this is because the NZ one is not a receiver hitch setup like the OEM Aus or US versions.
I also wonder if the NZ version has the brackets that mount up inside the chassis rails.
I'm unsure who actually makes the Aus version but the plate on it has BWM Australia written on it.