Argument null exception thrown while changing the calculation
type to DifferenceFrom, PercentageOf and some other types. Also null reference exception thrown while changing the calculation
type to "Formula". Need to add the "BaseField" and "BaseItem" options in the PivotComputationInfo pop-up.
1.Run the attached demo
2.Double-click "Amount" to bring up the pivot computation information dialog.
3. Change "Summarize Value By" to "Difference from".
4.Then click the "Ok" button.