If you are going to embark on a long game, and are trying to change your leaderboard then it's important your team knows that the game must end completely. All of the players who start the match, must finish it. They all must die. The game must end, and bring them all back to the lobby. Otherwise it's not going to count. Also,if you're hosting a private match, try to have a player with NAT open host it. Wrong.. people always leave in the middle and my leaderboard never changes and everyone else who stays counts accept for mine and certain other people.