Sub Boutons()
Dim Bouton As Shape, TxtBouton As String, AncFact As Long, NouvFact As Long, _
TV() As Variant, C As Long
Set Bouton = ActiveSheet.Shapes(Application.Caller)
TxtBouton = Bouton.TextFrame.Characters.Text
If TxtBouton = "Initial" Then NouvFact = 1 Else NouvFact = Mid$(TxtBouton, 2)
On Error Resume Next
AncFact = [FactMult]: If Err Then AncFact = 1
On Error GoTo 0
ThisWorkbook.Names.Add "FactMult", "=" & NouvFact
With ActiveSheet.[A1:E1]
TV = .Value
For C = 1 To 5: TV(1, C) = Round(TV(1, C) * NouvFact / AncFact): Next C
.Value = TV: End With
End Sub