XL 2010 changement de couleur de police de cellules d'un tableau en fonction de leur ordre chronologique

Private Sub Worksheet_Change(ByVal Target As Range)
Dim P As Range
Set P = [N21:P30]: If Not Intersect(Target, P) Is Nothing Then Couleur P
Set P = [N35:P44]: If Not Intersect(Target, P) Is Nothing Then Couleur P
If Not Application.Intersect(Target, [B21:L30,B35:L44,R21:R30,Z35:Z44]) Is Nothing Then
    Application.EnableEvents = False
    On Error Resume Next 'Pour passer outre l'erreur en cas d'effacement
    Target = UCase(Target)
    Application.EnableEvents = True
End If
End Sub

Sub Couleur(P As Range)
Dim d1 As Object, d2 As Object, i&, x$, n&
Set d1 = CreateObject("Scripting.Dictionary")
Set d2 = CreateObject("Scripting.Dictionary")
For i = 1 To P.Rows.Count
    x = P(i, 1) & Chr(1) & P(i, 3)
    d1(x) = d1(x) + 1
Next
For i = 1 To P.Rows.Count
    x = P(i, 1) & Chr(1) & P(i, 3)
    If d1(x) > 1 Then
        If Not d2.exists(x) Then n = n + 1: d2(x) = n
        P.Rows(i).Font.Bold = True
        Select Case d2(x)
            Case 1: P.Rows(i).Font.ColorIndex = 3 'rouge
            Case 2: P.Rows(i).Font.ColorIndex = 5 'bleu
            Case 3: P.Rows(i).Font.ColorIndex = 46 'orange
            Case 4: P.Rows(i).Font.ColorIndex = 14 'vert
            Case 5: P.Rows(i).Font.ColorIndex = 53 'brun
        End Select
    Else
        P.Rows(i).Font.Bold = False
        P.Rows(i).Font.ColorIndex = xlAutomatic
    End If
Next
End Sub

Sub Couleur(P As Range)
Dim col, fusion, ub%, i&, j%, n&
col = Array(2, 6, 10, 12, 14, 16, 18)
fusion = Array(4, 3, 2, 2, 2, 2, 2)
ub = UBound(col)
Application.ScreenUpdating = False
Application.DisplayAlerts = False
P.EntireRow.UnMerge 'défusionne
P.EntireRow.Sort P(1), xlAscending, P(1, 3), , xlAscending, Header:=xlNo 'tri sur 2 colonnes
For i = 1 To P.Rows.Count
    For j = 0 To ub
        P.EntireRow.Cells(i, col(j)).Resize(, fusion(j)).Merge 'refusionne
    Next j
    If P(i, 1) & Chr(1) & P(i, 3) <> P(i - 1, 1) & Chr(1) & P(i - 1, 3) Then n = n + 1
    P.Rows(i).Interior.ColorIndex = IIf(n Mod 2, xlNone, 15) 'alternance de couleurs
Next i
End Sub