-- Sim results
If you sum the number of checks over 10k simulations you get this :
=== FINAL RESULTS ===
Sequential: 495816995
Prefix: 496059807
This is a bias since the prefix method wins most of the time, meaning it is the best choice. When the prefix method loses, it obviously generates more keys because it is assumed that the target was omitted. And the goal is to find your best option to win and not who loses worse.