procedure TGrid_Form.qryGridCalculateField(Sender: TIB_Statement;
  ARow: TIB_Row; AField: TIB_Column);
var
  lvVal: Double;
begin
  inherited;
  with AField do begin
    if FieldName = 'C_LOSS' then begin
      with ARow do begin
        lvVal := ByName('COST_PRICE').AsDouble;
        if lvVal = 0 then begin
          lvVal := 0;
        end else begin
          lvVal := (lvVal - ByName('CURR_VALUE').AsDouble) * 100 / lvVal;
        end; { if }
      end; { with }
      AsInteger := Trunc(lvVal);
    end; { if }
  end; { with }
end;