You do not need to recreate the style. All you need to do is adjust when needed. I have found that one quick way to do that is to right-click (or, highlight then right-click) on the text where you want to restart (at 3. or c. - whatever number/letter style you are using). A popup menu will appear - then click on "Restart at 1" or "Restart at a" (again, whatever number/letter style you are using).

Hope that helps...