[boxhead]

I presented my car with the harness belts only for engineer, he questioned the NT MVR in the hope of my car being approved with the harness belts only.
This was not allowed as he could not find a precident (since then I have heard of some WA guys being approved), The NT MVR guy told me that I can present the car with both types fitted, as there only concern was that the vehicle had approved seatbelts, any other belts was not there concern as long as they did not affect the fitment or impead the retractable belts.
I suppose it is the same regarding wipers, if you can get the correct wipe percentage with 2 blades that is great, but there is also no problem with fitting 3 and wipeing a larger area.