revisiting the old ball

So I did the bouncing ball earlier. But I wasn't informed of the squash and stretch principle yet. So time to fix up this bounce. So apparently on the contact the ball needs to be squashed, the ball needs to stretch as it gains momentum before the contact, and it needs to return to its volume as it slows down at the peak of its bounce.
So lets do this.
Ive opened up my old bounce scene file.
I go to my contact frames and I begin to scale the ball(r on the keyboard in maya). I notice that as Im scaling the volume of the ball doesn't always stay consistent. So I need to scale in at least 2 axis to keep the volume or mass the same. I notice as well that by default the volume of the ball is 1 in all 3 axis. So in order to maintain the correct volume I started with all 3 axis should always equal 3 when added together. Ok simple enough. I scale the x axis to 1.4, and I scale the y axis to .6 with z equalling 1, I now have a squashed ball that is of the correct volume. On the next contact I make x 1.3 and y .7 as the impact isn't quite as hard. So now I need the ball to return to it's volume again so I set a new scaling key of 1 in all the axis again at the peak of the bounce. Now it's a little tricky trying to maintain the volume perfectly as I work in the graph editor so I have a little trick ive made up. I open both the y and x axis scaling curves. I add a breakdown key with both curves selected(I on the keyboard and mmb click) and I turn my scale tool on(r) and grab both breakdown keys at the same time. I click on the 1 line and can now scale them both to where I want the breakdown to be and they move exactly the same so the breakdown volume still = 3 and the journey to it will always = 3 as well. Here is an image of how that looks.

I play my animation, and it looks very funny. I need to definitely add some rotations to this for the shape to look like its supposed to. So I turn on my rotation tool(e in maya) and lets set some keys. I know the rotation should be 0 on the contact frames, so I add that. I add the rotations for before, and after each contact frame, and I set my curves to linear. Since the rotations are 70 and - 70 it balances out nicely and I dont need to add any extra curves to this. Since it reaches 0 at the peak frame everything works nicely.

Here is the image of the final bounce with squash and stretch now.

Once more but this time lets apply what Ken Harris said. Have the ball contact and then squash. Notice the difference here.