Hi I'm trying to insert a calculated row in a pivot table. I keep getting the error message 'Pivot table items can only refer to items in the same field as the calculated item'

Please help. Below is the format of my data.

Cheers in advance


Region (All)
Sub Division (All)
Sub Cluster (All)
Cluster (All)
A/C Level 3 (All)
A/C Level 1 (All)
A/C Level 4 (All)
A/C Level 5 (All)
Division (All)

Values
A/C Level 2 Sum of FY11 Sum of FY12 Sum of FY13
Net Revenues 100 200 300
Op Exp 50 40 30
Calculated Field 50 160 270