I have created a Pivot Table (source is an OLAP Cube) and I would like to
create a calculated field that is the difference between 2 columns (not the
total), but since my source is an external OLAP cube I can't use the Pivot
Table toolbar function to create a calculated field. I have created the
Pivot Table in Excel 2007.

Is there a way to do this with VBA using the existing Pivot table that I
created? If so, how?