ecrire une formule si condition

Bonjour,

Un peut d'aide pour modifier ce bout de prog qui ne fontionne pas

Merci d'avance





Private Sub Worksheet_SelectionChange(ByVal Target As Range)

If Range("b2") = "DEVIS" Then
Range("f30") = "" 'acompte facture
Range("b29") = "Acompte le"
Range("D30") = ""
Range("d28") = ""
Range("f27") = "" 'efface cellule
Range("d27") = ""
Range("b27") = "Devis valable 2 mois"
Range("d29") = ""
'Range("a1").Select
Calculate
Else
If Range("b2") = "FACTURE" Then
Range("B30") = ""
Range("b27") = ""
Range("d27") = "TOTAL HT"
Range("d28") = "TVA"
Range("F27").ActiveCell.FormulaR1C1 = "=SUM(R[-13]C:R[-1]C)"
Range("F28").Select
Range("d29") = ""
Range("b29") = ""
Range("D30") = "Acompte le"
Range("d31") = "TOTAL TTC"
'Range("a1").Select
Calculate
End If
End If


End Sub