Bro I was having a massive headache because for some reason AE was putting a 16% influence on every new keyframe I add.
Solution:
1) Open the Velocity window (Ctrl+Shift+K) of THE LAST keyframe you have added to the layer.
2) Make sure ALL outgoing and incoming velocities are set to the number you want.
The confusing part here is that even though you may initially have the exact curve you want, the outgoing velocity of that last keyframe could be anything and it won’t affect the animation. What it WILL affect is the next keyframe you create after it: it will have incoming and outgoing velocities like the last one you made.
I know that’s not exactly what you were asking, but it will definitely help some people who will end up on this thread.