Punta, it depends on which way you look at it
If it is going to be another replenishment ship it makes sense, and in a 3 ship AOR build it means that all 3 would be built in Spain (which would not go down well politically). However, their is every possibility it may not be another AOR at all.
The other possibility is that is could be a Logistics Support Vessel. At this stage the RAN do not know what they want (if they do it is not in the public domain), the commitment so far is a couple of lines in the latest DWP and it is either for 3 AOR's and 1 LSV, or 2 AOR's & 2 LSV's.
HMAS Choules is due for retirement at the end of the 2020's which is when a commitment for either another AOR or an LSV would be due for delivery.
If Choules is going to be replaced it would make every one very happy if it was built in Australia. It would be even better if it was a two ship build. For this to happen the nominated build site (probably SA) would probably have ot be upgraded to allow for the larger build.
It is not inconcievable that if an LSV is selected it could have a small replenishment capability, but this is pure speculation on my part.