première macro - assistance recommandée

Sub boucle_indicateurs(paramètre1 As String)
       if paramètre1 = "Pascouleur" then
              range("C3:I8").interior.colorindex = xlnone ' possibilité de travailler en une fois sur la plage complete
              range("C3:I8").font.bold = false
              exit sub
      end if
       Application.ScreenUpdating = False
       Dim c as range ' declaration de la varialble c comme une cellule
       For each c in range("C3:I8") ' c etant une cellule, c.value contient sa valeur, pas besoin de la selectionner avec un select
      Select Case (c.value * 100) / cells(3,c.column).value
           Case 0 To 25 '<25%
               c.Interior.ColorIndex = 3
               c.Font.Bold = True

           Case 26 To 50 'de 25% à 49%
               c.Interior.ColorIndex = 46
               c.Font.Bold = True
           Case 51 To 75
               c.Interior.ColorIndex = 42
               c.Font.Bold = True
           Case 76 To 100
               c.Interior.ColorIndex = 4
               c.Font.Bold = True
       End Select
       Next
       Application.ScreenUpdating = True
End Sub

Option Explicit
Sub boucle_indicateurs(paramètre1 As String)
Dim c As Range, celluleorigine
Application.ScreenUpdating = False
celluleorigine = ActiveCell.Address
For Each c In Range("C3:I8") 'plage a testée
  If paramètre1 = "Couleur" Then
    Call Colorer_les_Chiffres(c)
  End If
 
  If paramètre1 = "PasCouleur" Then
    Call raz_couleur(c)
  End If
Next
Application.ScreenUpdating = True
Range(celluleorigine).Select
End Sub
Sub Colorer_les_Chiffres(Cel As Range)
Dim pourcen, valeure, Lig As Long
valeure = Cel.Value
Lig = Cel.Row
pourcen = (valeure * 100) / Range("B" & Lig).Value
Select Case pourcen
  Case 0 To 25 '<25%
  Cel.Interior.ColorIndex = 3
  Cel.Font.Bold = True
 
  Case 26 To 50 'de 25% à 49%
  Cel.Interior.ColorIndex = 46
  Cel.Font.Bold = True
 
  Case 51 To 75
  Cel.Interior.ColorIndex = 42
  Cel.Font.Bold = True
 
  Case 76 To 100
  Cel.Interior.ColorIndex = 4
  Cel.Font.Bold = True
End Select
End Sub

Sub essai()
a = 25
Select Case a
    Case 0.01 To 25
        MsgBox "1"
    Case 25.01 To 50
        MsgBox "2"
    Case 50.01 To 75
        MsgBox 3
    Case Else
        MsgBox 4
End Select
End Sub

Sub essai()
a = 25.005
Select Case a
    Case 0.00000000001 To 25
        MsgBox "1"
    Case 25.00000000001 To 50
        MsgBox "2"
    Case 50.00000000001 To 75
        MsgBox 3
    Case Else
        MsgBox 4
End Select
End Sub

      Select Case Round((c.Value * 100) / Cells(3, c.Column).Value, 2)
             case 0 to 24.99
             case 25 to 49.99
             case 50 to 74.99
             case else ' >= 75
      end select