The other side of the coin is the question of how often you reference the old chart and how much more time would it take if you don't separate sections.
It will certainly take more time to divide up the scanning, but really doesn't take much time to find the relavent material when you know the chart structure without separations.
After about 6-12 months you will find you don't reference the old chart that much, the information is in the new chart.
As to Updox, I have heard great things but don't use it, I defer to Jon's post which indeed seems a useful way to do it.
As Jon said, there are many different ways to accomplish what you want to do. You just have to set your priorities.
