Problems with Totals and Subtotals of a Calculated Item in a Pivot Table

Hi everyone, I have an issue with a calculated item in my pivot table, because in the totals and subtotal it shows the sum of the column but I want to show the formula that I've specified to the calculated item.

For example, in the attached file, I have in rows the field "name" that has four values (A,B,C,D), in columns the field "Groups" that has "G1" and "G2". I add in the rows the calculated item "G1/G2" that has the formula G1/G2. The problem is that in the total the column "G1/G2" doesn't show the division of the total of "G1" and "G2".

Someone have a solution for this problem? Thanks!

Regards,

Gever.