To just make the bone go back and forth, you really only needed the driver on one of the constraints, not on both? So you didn't have to copy from the first to the second constraint?
No you don't need to copy from the first to the second, but what I was trying to show in this demo is how you CAN copy and paste stuff and THEN edit it.
Knowing that you can do this will save you so much time.
For example when you need the same driver from the left side to the right side. You can copy and paste it, then just change the .L to .R and you are done.
The reason you don't need the two drivers is because of the way the constraint stack works.
It will be calculated from the top down, so the second constraint will override the first one.
I hope that makes sense.