I booked award travel today (yvr-syd-akl-syd-yvr with a 8-day stopover in syd and a 5-day stay in akl) on ac/nz mixed and I was a little concerned that the routing would be disallowed as we might be backtracking. I asked the agent to confirm the rules and she put me on hold for about 4 minutes to engage her supervisor. Everything checked out OK according to them, but it might be worth asking them to double check your award itin if it's not a straightforward one!