XL 2019 comment mettre a jour une cellule par rapport à une autre cellule

Private Sub Worksheet_Change(ByVal Target As Range)
    Dim ws As Worksheet
    Dim cellToUpdate As Range
    Dim cellType As String

    Set ws = ThisWorkbook.Worksheets("Balance system")

    If Not Intersect(Target, Me.Columns("D")) Is Nothing And IsNumeric(Target.Value) Then
        cellType = Target.Offset(0, -1).Value

        Select Case cellType
        Case "A"
            Set cellToUpdate = ws.Range("D12")
        Case "B"
            Set cellToUpdate = ws.Range("D13")
        Case "C"
            Set cellToUpdate = ws.Range("D14")
        End Select

        If Not cellToUpdate Is Nothing Then
            cellToUpdate.Value = cellToUpdate.Value + Target.Value
        End If
    End If
End Sub