Code très lent

Option Explicit
Private Sub CommandButton1_Click()
'
'----------------------------
Dim DerLign        As Range
'----------------------------
Dim Cel            As Range
'----------------------------
Dim i              As Byte
Dim l              As Byte
'----------------------------
Dim OldCalculation As Long
'----------------------------
Dim Tableau()      As Variant
'----------------------------
'
  With Application
    OldCalculation = .Calculation
    .Calculation = xlCalculationManual
    .ScreenUpdating = True
  End With
 
  Set DerLign = Sheets("Database").Range("a65536").End(xlUp)
 
  If TextBox63 = "" Then
    MsgBox ("Il faut indiquer le nb de jours")
    Exit Sub
  End If
 
  l = TextBox63.Value
  ReDim Tableau(1 To l, 1 To 5)
 
  With Me
    For i = 1 To l
      If i = 1 Then
        Tableau(i, 1) = DerLign + 1
      Else
        Tableau(i, 1) = Tableau(i - 1, 1) + 1
      End If
      Tableau(i, 2) = CDbl(.Controls("TextBox" & i))
      Tableau(i, 3) = CDbl(.Controls("TextBox" & i + 31))
      Tableau(i, 4) = Tableau(i, 2) + Tableau(i, 3)
      Tableau(i, 5) = Tableau(i, 4) * 160#
    Next i
  End With
 
  DerLign.Offset(1, 0).Resize(UBound(Tableau, 1), UBound(Tableau, 2)) = Tableau
 
  With Sheets("Recap")
    On Error Resume Next
    Set Cel = .Range("E:E").Find(Tableau(1, 1), .Range("E1"), xlFormulas, _
                 xlWhole, xlByColumns, xlNext, False).EntireRow.Calculate
    If Err <> 0 Then
      Err.Clear
    Else
      Call MajGraph.MajGraph
    End If
  End With
  On Error GoTo 0
 
  With Application
    .Calculation = OldCalculation
    .ScreenUpdating = True
  End With
End Sub