How do I get two or more horizontal category rows on top centered
 

When I have 8 categories showing in the horozontal menu bar they show centered. I have the setup in ATO > Header Area > Style & Edit Header Area > using %cat-center (with no s).

When I add a 9th category to there is a second line created (too many to fit on one line) and they are all moved to the left.

When I change back to 8 categories it all works perfect again (they are all centered)

How can I center 2 or more rows of categories?

Thank you,
Doc