change formation or use only one?

[dv8r]

as you i did the same , used a lot formations to counter the opponent and in the end i failed more then using the same formation !
i think the team gets an extra edge using the same formation all the time , since with the same formation only once at 10 matches i draw or lose ... and when i change the tactic i draw or lose more often ...

P.s. every manager has his luck too

One person in my league uses the same formation every game and she wins 5+ goals. I try to counter and only win by 3+ goals usually