Pivot Tabe Duplicate Grand Total
 

Good Morning All, XL2007
I have a basic PT summing vales across a row of months.

A B C D
Overheads 10 10 10
Expenses 20 20 20
Grand Total 30 30 30

Now I wish to insert another Grand Total Row which will show
the Running Balance ie

A B C D
Overheads 10 10 10
Expenses 20 20 20
Grand Total 30 30 30
Grand Total(2) 30 60 90

I know I could add a seperate row outside the PT to reflect the
Running Total, but would rather keep it included, via a
Calculated Field or such like.
I have managed to contrive a Calculated field, but this returns Subtotal
rows
for the Running Balance for all my Subdivisions, eg Overheads, Expenses etc.
I wish just the Grand Total(2) to show the Running Balance.

Is there a way?

As usual thank you for any input.
Cheers
Mathew