This is because the expression returns an array. Can you send a snapshot of your data - the field of interest is the "Total_Current_Charges".

Since you have category grouping, you may need to update your expression with FIRST for the Total_Current_Charges e.g.:

=IF(FIRST(Fields!Total_Current_Charges)<20, "Less than 20 OMR",
IF(FIRST(Fields!Total_Current_Charges)>35, "Greater than 35 OMR", "Between 20 and 35 OMR")) + " - " +
FORMAT(SUM(Fields!GrossProfit.Value), "N0", "en-us") + " - " +
FORMAT((SUM(Fields!GrossProfit.Value)/SUM(Parent.Fields!GrossProfit.Value)), "P0", "en-us")

Best Regards,
Nevron Support Team

Thanks for your prompt reply.  I made the recommended changes (screenshot of two Format statements); but now gives me an error.

You can’t pass category labels to the pie chart data labels like that. Also, you should not use the FORMAT function in the Data -> Value field.

You should consider using only <label> in the Data Groupings -> Values -> Data Labels -> Format field:


Then, in the Data Groupings -> Values -> General -> Data -> Label field, use an expression like this:
=IF(Fields!Total_Current_Charges<20, "Less than 20 OMR",
IF(Fields!Total_Current_Charges>35, "Greater than 35 OMR", "Between 20 and 35 OMR")) + " - " +
FORMAT(SUM(Fields!GrossProfit.Value), "N0", "en-us") + " - " +
FORMAT((SUM(Fields!GrossProfit.Value)/SUM(Parent.Fields!GrossProfit.Value)), "P0", "en-us")

Best Regards,
Nevron Support Team

I am unable to pass the "Label" from a Category Data Grouping.  I am grouping by Category to distinguish costs:
Labels are "Less than 20 OMR", "Between 20 and 35 OMR" and "Greater than 35 OMR".  The logic for each of the Category groupings is working fine e.g. (=Fields!Total_Current_Charges<20) and displays the <value> and <percent>, but the Label I assign to each Category grouping does not get passed back to the chart.  Below is a screenshot of my configuration.
Thanks in advance!