In low level league, I suspect that there are added parameters to win games constantly every time we level. In high level league, these parameters importance will change every season. That's why it's very hard to read how the engine works. Beside that if you win a league I suspected that our next league will be with teams that just have the opposite practice and the way we manage our team (natural nemesis). That's why sometime our winning percentage drops significantly using the same team every new season.
In your case, I think that your team have hidden weaknesses. Your stat is higher than opponent but your team can not score. You need to train your attacking players to shoot, improve set pieces and finishing. The stats of the players sometime deceiving because the game count how and what kind of drill you trained you players. Beside that I think the most important thing is balance so that your team will play consistently. What it mean is your strategy, drills of choice and formation must correspond each other. In order to do that we must try to figure how the opponent will setup his teams. Sorry for bad english.