Copy-Paste anything you want, then get it from anywhere.

protected void ASPxGridView1_CustomUnboundColumnData(object sender, ASPxGridViewColumnDataEventArgs e)
  {
        if(e.Column.FieldName == "Variance")
        {
            double total = 0;
            for(int i = 1; i < ASPxGridView1.VisibleRowCount; i  )
            {
                total  = Convert.ToDouble(ASPxGridView1.GetGroupSummaryValue(0, ASPxGridView1.GroupSummary["IPOTEK"]));
            }
            
        }
  }