Performance graphs are still available in the AFM as said above. However in the real on the line world i haven't seen a graph in the last 15 years or so. It was tables in books, and for the last 7 years its been a performance program on an EFB. Those are extremely precise right at the edge of the possible performance, therefore one needs to be very careful what options to activate and which values to enter. As someone mentioned above standard weights alone will bring quite a big uncertainty factor into the game.