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