zooming animation is not smooth in Premiere CS6 Animatedly, I tried to zoom into a video clip in Premiere by creating two Position keyframes and two Scale keyframes

But the result is very shaky for some reason?
What am I doing wrong with this implementation, or should I achieve this zooming effect by other means?
Same shaky result using linear interpolations
If I use just Position keyframes (Scale keyframes deleted for troubleshooting), and if I set the keyframes' Temporal Interpolation to Linear and also the Spatial Interpolation to Linear, the resultant video is still jerky, as evidenced here

I set the temporal and spatial interpolations to Linear for both keyframes i.e. for both the starting and middle keyframes


There are a number of other interpolation options, maybe one of them would help?
Turns out that one should use the Motion effect and not the Transform effect for zooming in Premiere, even though they have exactly the same Position and Scale controls!

Here is the result with the Motion effect

p.s. The Anti-Flicker filter I discovered under the Motion effect was left to the default of 0, so that was not needed.

p.p.s. I also found this discussion of a similar issue