That's not always how it works. Sure the game will scan frequencies for the best possible host, but, there could always be someone in there better than yours. The main problem with the host migration is differing from where most of the players originate from. You can have 2-3 people from the USA so they will use your connection, but then you have the rest of the players in Europe where your connection just completely fails behind reason. Its more of a majority host depending on where most of the players are located and if you can lock on to that certain area.