Training
PF had practiced the UAS out of Rio on the Simulator three months ago (with this PNF ?) which was a 15 degree climb and TOGA, ( for lower levels). He may have tried to do just this. He was slow in increasing his thrust to TOGA on AF447. But he may have decided that this was the correct drill. His mind was set.
I have mentioned earlier one fleet in the sixties, where, in the Crew Room it was joked "that it did not matter which Drill you did... so long as you did it quickly."
More training ? Garage Years #644, says that his simulators are in use 20 hours a day with 4 hours for maintenance. One of AB's sales lines was that conversion from one AB to another AB was simpler..