Well, I don’t want to spoil your thrill but I ‘m tending to believe that rates aren’t such a big deal. The game/program consider the quality of the players, the formation/orders, the condition of the players and don’t know what else and making a decision who’s gonna win.
After that, the program making a visualization of the process which is what we ‘re seeing.

If we have a 2* player among other good players of the team and with good other factors, this player can have a good rate, but if we have a team of 2* players or playing with a 4-5 level up team in the Cup or in a friendly game, no matter if our team is in an excellent form, we can’t win. Sometimes I believe, the program decides to favor a weak team (hey, it’s football) .
Personally, rate of a player is very low in my opinion, for evaluation of a player I want to buy.

+1 point to the game : many times I feel like my players have some some individual personalities and reacting like this.

-1 point : Sometimes the program fail to create the right visualization of the game and we see it as a troll result. A classic fail of the game is when the GK gets injured.

Click image for larger version. 

Name:	injury GK.jpg 
Views:	35 
Size:	45.9 KB 
ID:	33015