pivot table calculated fields
 

is there a limit on how many fields you can have in a pivot table in order to
insert a calculated field? i have 10 columns...if i create the pivot with
all 10 columns, and then try to insert a calculated field between columns a &
b to show b/a, nothing happens. however, if i create the pivot table by
adding columns a and b, then inserting a calculated field to perform b/a, the
results appear, but when i repeate these steps to create the rest of the
pivot table, the calculated field no longer appears after 3 have been
inserted. is there any way around this?