I'm not sure stacking upgrades in this way can be achieved, but don't have personal experience.
OT (slightly), for my upcoming stay at Novotel AKL I had previously contacted the hotel directly to signal interest in upgrade (I am Accor Gold). A few days ago I received an email essentially offering 2 kinds of 'up-sell' to the room, the first level was for $0, presumably because it is a status benefit.