I'll go to your second question first. Only one has a legislative mandate: the Australian PBO. In the Netherlands the office does the calculation of the electoral platforms, but it doesn't have the legislative mandate. In the Netherlands it was created in 1947, so it has a long experience. There are about 12 parties, so it's a different story over there.
One, then, has a legislative mandate, which is the Australian one.
I will ask Jason, who is the senior director who will be in charge of the costing of the electoral platforms, to explain how he will do it. Since I will not be there, I'd prefer to ask him to answer your question.