How to delete part of chart datalabels?

[alee001]

I had spend half day also cannot solve this problem, anyone know what reason and solve?Thanks.
Each press F9 key to refresh formula and make random signal(i.e. "L", "S", "W"), VBA always error '-2147467259(80004005)' on .Points(r).DataLabel.Delete

Private Sub Worksheet_Calculate()
Dim sys As Worksheet
Dim dat As Worksheet
Dim cht1 As Chart
Dim srs As Series
Dim r6 As Integer, r7 As Integer, r As Integer, v As Integer
Dim nowPt As Integer, signalPt As Integer
Dim sig As String
'On Error Resume Next
Set sys = Sheets("System")
Set dat = Sheets("Data")
Set cht1 = sys.ChartObjects("Chart_market").Chart
Set srs = cht1.SeriesCollection(4)
With srs
    If Range("chart_period").Offset(0, -1) > dat.[Q1].End(xlDown) Then
        If Range("chart_period") = Range("chart_sel") - 1 Or Range("chart_period") = Range("chart_sel") Then
            v = 0
        Else
            v = Range("chart_period").Offset(0, -3)
        End If
        nowPt = Application.Match(Range("Backtest_to"), Range("data_rng"), 0) - v
        r6 = Application.Match(dat.[Q1].End(xlDown), Range("data_rng"), 0)
        r7 = Range("BE5").End(xlDown).Row
        For r = nowPt + 1 To .Points.Count - 1
            If .Points(r).HasDataLabel Then
                .Points(r).DataLabel.Delete  'clear prior datalabels
            End If
        Next
        For r = 1 To r7 - r6
            If Range("BE" & r6 + r) <> Range("BE" & r6) Then
                sig = Range("BE" & r6 + r)
                signalPt = nowPt + Application.Match(sig, Range("BE" & r6 + 1 & ":" & "BE" & r7), 0) - 3
                .Points(signalPt).ApplyDataLabels
                With .Points(signalPt).DataLabel 'add signal label
                    With .Format.TextFrame2.TextRange.Font.Fill.ForeColor
                        If sig = "S" Then
                            .RGB = RGB(255, 0, 0)
                        ElseIf sig = "L" Then
                            .RGB = RGB(102, 255, 51)
                        ElseIf sig = "W" Then
                            .RGB = RGB(255, 0, 255)
                        End If
                    End With
                End With
                Exit For
            End If
        Next
    End If
End With
Set sys = Nothing
Set dat = Nothing
Set cht1 = Nothing
End Sub