Visual Basic - Ayudame para Restar monto y sumarizar con flexgrid

Private Sub cmd_Calcular_Click()

Dim dvalor As Double

Dim Fila As Integer

dvalor = 0

Dim i As Double

Fila = Me.grid1.Rows

For i = 1 To Me.grid1.Rows - 1

    If dvalor = 0 Then

        Me.grid1.RemoveItem (i)

    Else

        dvalor = Val(grid1.TextMatrix(1, 1)) - Val(Text1.Text)

    End If

Next

   grid1.TextMatrix(1, 1) = dvalor

   Sumarizar

   Text1.Text = dvalor

End Sub

Private Sub Form_Load()

Dim i As Integer

grid1.Rows = 1

grid1.Cols = 2

grid1.TextMatrix(0, 0) = "Item"

grid1.TextMatrix(0, 1) = "Valor"

grid1.AddItem "1" & vbTab & FormatNumber("500", 2)

grid1.AddItem "2" & vbTab & FormatNumber("800", 2)

grid1.AddItem "3" & vbTab & FormatNumber("1200", 2)

grid1.AddItem "4" & vbTab & FormatNumber("100", 2)

grid1.AddItem "5" & vbTab & FormatNumber("630", 2)

Sumarizar

End Sub

Private Sub Sumarizar()

 Dim dvalor As Double

 dvalor = 0

 For i = 1 To grid1.Rows - 1

 dvalor = dvalor + CDbl(grid1.TextMatrix(i, 1))

 Next

 TextoTotal.Text = FormatNumber(dvalor, 2)

End Sub