Booked FLR-FRA-ORD-RIC for my wife a few days ago, PZ9 for FRA-ORD and GPU cleared at time of booking. Flight went to PZ0 since then, and even after I booked the same itinerary still showing PZ0. However, after ticket was issued, I went in to apply GPU and FRA-ORD cleared immediately. Moral of this story is PZ0 may still have upgrade availability.
Now I have to figure out if ORD-FRA is truly PZ0.