I just could NOT get the second modification working using the Project 5 (and sometimes Project 6) code... no matter how I modified it, I could not seem to find a way to tweak the code just a little bit to "bounce the ball." My best guess was that it would involve some sort of counter that would limit the value that CurrentLED would count up to each time (reducing it from 9... to 8... to 7...) but again... no luck with that.
So... I decided to simply hard code it to do what I wanted. I kept the array (see screenshot of my code) but got rid of much of the variables, including the CurrentLED variable, and went straight to a set of embedded FOR loops that would first loop 9 times (for nine LEDs - the ball bouncing up)... then 1... then 2... I created a variable called bounce that would simply decrement in the code every time the second loop (the ball dropping) finished. Probably not the most elegant solution, but it worked. You can download my code modification here.
I welcome my readers to share their code if they managed to perform the 2nd modification on page 58 using a different method... I'd love to see a few other programming techniques if anyone wants to share.