Custom Games Connection Host.

I have a question.

When playing Custom games on Halo 4, who is the connection host? Is it the always the Party Leader or is it like Matchmaking where the game will pick the person with the best connection?

Just asking because when playing custom games myself. I’ve never seen a selecting new connection host screen pop up, even when experiencing bad lag. However, when experiencing bad lag, switching party leader seems to sort the problem out.