So here is how to subtotal a column that is itself a sum function. SSRS 2005 wont allow you to aggregate an aggregate function. For example, the total of a column showing a Running Total, useful in daily stock balance calculations.
Add the following code to the report Report > Properties
Dim public totalBalance As Decimal
Public Function AddTotal(ByVal balance As Decimal) AS Decimal
totalBalance = totalBalance + balance
Public Function GetTotal()
This code adds two variables: totalbalance and cnt as decimal numbers. And two functions AddTotal and GetTotal.
AddTotal allows items in rows to be added up, use as follows in a value cell, where you had;
in the total cell, where it you were unable to simply use
Simply add more variables and public functions if you need to sum the sum of more that one field.
Inspired by this post on averages of averages link