Simple, to have a "ratings push" in a finale, you need to synchronize as many players as posible with a rating drop.
If, a player had a 8-7-8-8-6, and you have like -League and CL finale- save him to keep that 6 drop until the finale, so he'll probably earn a push. You can ofc. set one who got a 10 to drop intentionally his rating playing without condition and a wrong setting.
Some poeople, too, sets a FA game with a -30% condition player so the game is cancelled and this seems to reset the ratings to lower ones.
The variations affect the upcoming match scenario, so you can, at some point control who will have a chance to be determinant by forcing the engine, to select him for a posible push, like for example, a Key player usually gets 2-3 Max ratings... max is 9-10 (are the same both), so, if, a key player got 9-8-10-9-10 after the streak of 3 max rating syou can expect a drop, meaning this that the engine will not select him to be determinant in the next game. So in this case, you need to force the engine to keep saved a previous lower rating than this 10.
Variations