i have no knowledge of the advance editor but i know that if you want it to be 3 wins then it would have to be best of 5.
think about it like this, if you want them to have to win X games to advance then the closest outcome will always be 2X-1. in the scenario you've asked for if it went to a last game decider then it would end up 3-2 to the team that went through meaning they would have played 5 games.