Rolex 1575 is an automatic. It should not make a difference about how much power you have running through the movement. Did you use the correct oils, you might have used to much or to little. You need to let it settle down and then test, that will give a good average of the movements performance
I often wonder about that too. Surely if the manufacturing process was well controlled, then there would be no need for them.
Perhaps their original intention was to allow for thinner and thinner shims at each service, as the pivot ends wear, but that is just speculation on my part.
What I do know is that they represent one more thing for me to ping into a parallel dimension, or simply forget to refit, risking damaging the jewels and pivots in the process, so perhaps they are simply intended as a trap for the uninitiated.