In OZ, min 2000ft is separation is required from an aircraft at FL415.
Mmm, I don't see the logic of that if both aircraft are RVSM approved and one is at FL400 and one is at FL415. They are separated with one at FL400 and one at FL410 (1000') so why are they not separated when they have an excess of that separation standard ?
If you instructed one pilot to fly at FL400 and the other to fly at FL410 or above, you would have separation would you not ?? That's exactly what you are applying here.
The rules don't have to always be blindly followed, sometimes you have to think about what is being said and then apply them as they were actually intended without adding complications which simply don't exist.