showing exponent in ms word using field codes

Hi,
This is the field code I used for displaying an exponent in microsoft
word,

EQ y \s\up6(9)
EQ \f(y,x) \s\up6(9)

I wrote a program to dynamically set the field codes in word, but here
how can I adjust what is the value required to show the exponent,
position of exponent needs to be adjusted based on the base height