Do association games have a different game engine?

[Abbas]

I am playing my first season in an association and I have great results. Winning and drawing against teams that are 20/30% stronger, even when the other manager attends, and demolishing teams that are 20% less (latest result 11-0 Without attending).
When playing league, CL or cup matches all seems a bit different and I have a hard time against Teams that are 20% weaker and I hardly win against teams that are about as strong as my squad.

Anybody any idea?

Most association players are tankers (MOST of them), they have no tactics and game play experience whatsoever.