I decided to try and run a test. Conveniently, my game crashed just after losing to Aston Villa 2-0. I am playing Man U, near the end of the season. I've managed to maintain third spot in the League. I had saved just before playing the game since I've been having crash issues with the ME. I decided to run the game a few times from that save and see the results. I ran two more games after that with the same tactics each time. The first time I won 4-0 and the second time we tied 2-2. I didn't get any major issues, or have anyone sent off in any of the games, so there were no serious events to alter the outcomes. It seems like a large amount of variability for a single game. It also suggests my tactics selection doesn't really matter much.