In 2011 I introduced the five-parameter model, which I used to simulate the contest between Bookmaker and Punter by making different assumptions about the relative precision and unbiasedness with which they estimated the Home team's victory probability. The fifth parameter in the model was the total overround embedded in team prices by the Bookmaker and, as was my custom at the time, I assumed that the Bookmaker levied this total overround equally on both teams. Now, I think differently.