Different labeling formats in chart
 

I want my z axis to display 0%, 20%, 40%, 60%, 80%, 100% but the values over
my bars in my graph to display the fractions. Currently, I'm custom
formatting each cell to NOT display the fraction as the lowest common
denominator (very time consuming) then hiding z axis labels and using text
boxes to label it myself.

Can Excel be made to do either or both of the things I need:
-display % AND fractions
-display fraction as entered rather than lowest common or with custom format