I am working on a video and using various animations that move in and out of frame. And as a part of that, I was doing some tests on the various key frame interpolation settings. I know you can set each key frame to linear, smooth, etc... but there is also a Smoothness slider associated with the Key Frame type under Event Pan Crop and on the Track Motion Track Level. I did some tests with having the slider at 0 and another with it at 100, and honestly, I couldn't seem to see any difference. Whether the slider is at 0 or 100, I don't see any additional tweens added. Does anyone know what this slider does? Does it add hidden tweens or further adjust a motion curve or something? I just don't see much of a difference, and don't even know exactly what it's doing.

In the video, the gray, slower ball is with the Smoothness slider set to 100, and the red ball is with the slider at 0.