I sometimes wonder if stock D40 rotors are made by King Island Dairy Company and matured in wax for 8 months before installation. I dunno, I wonder if Nissan think they need to be made of something that would find playdoh a challenge in terms of hardness.
My car also had its rotors replaced at the 40,000km service.
D22s are a little lighter at the kerb and not supposed to drive like a sports car, which I think was Nissan's goal with the D40 as it leaves the factory, so they put softer rotors that bite better.