Calculated item in pivots

Hi,

I am facing this problem while adding calculated items in pivots. The calculated fields work till the point I have only 1 field in the row. When I add additional fields in the row the calculated row gets weird. It shows rows from other subsets in the pivot. I will try and explain with an example

My pivot looks like this-

Rows
Continent- country - company

Columns
Regions - Data from X/Y

Values

My calculated field shows any difference between values from x and y. This works till I have only company in the rows. If I enter additional fields like country/ continent, the same company appears in different countries though with zero data in it.
I can't figure out why