When you have an uneven distribution of roles in a queue, the bot should default to using MMR as a secondary method for balancing. For example, if you have 4 bronze players and 2 plat players, each team gets 1 plat player and 2 bronze players. However, if you have 3 of each, you can only do 1 bronze player and 2 plat players and 2 bronze players and 1 plat player. In this case, the bot should look at the MMR of the players and balance it accordingly. So the two bronze players would receive the plat player with the highest MMR.