error drilldown by fs item in formula

Hi all,

I created a formula wich contain boolean operator like this :

(fs_item_1 <=0)* (fs_item_1 + fs_item_2) + (fs_item_1 >0) * fs_item_2

the result is ok but when i do a drill down by fs item in order to see the amount in each account, it lacks an amount for one account it is empty and the

sum of all the acounts wich are display is not equal to the result of formula.

do you have an idea ?

how to resolve it?

thanks a lot

S.