Basically, the automatic duty works in accordance to your tactic's strategy. If you choose a more balanced strategy (Counter, Balanced or Control), every player with an automatic duty (FB, CM or WM) will act with a supporting duty. A more defensive strategy will of course make those players have a defending duty, and finally, an attacking strategy will ask more involvement of your players in the attacking phase, by making those players have an attacking duty. This automatic role is more useful if you have a more strict tactic and you change the strategy some times during a match. Other wise, is better to have those players have a more specialized role/duty.
