the formatnumber() function does not display decimal numbers that have more than 3 decimal

i have next code

Dim z As Range
Dim inputstring As String
Dim brojdecimalnihmesta As Integer
Dim DecSep As String
Dim ThousendSep As String
Dim CurrentSelectionRng As String
Dim eIndex As Long
Dim eRowIndex As Long


CurrentSelectionRng = Selection.Address
On Error Resume Next

MsgBox "Pre nego sto unesete format kolone: broj, tekst, datum, procenat; izaberite jednu celiju u koloni, koja ce biti selektovana", vbOKOnly
inputstring = InputBox(Prompt:="Unesi format kolone('b' - broj, 't' - tekst, 'd' - datum, 'p' - procenat", Title:="Format kolone")


 If inputstring = "b" Then
     MsgBox "Format celije(a) ce biti broj", vbOKOnly
    brojdecimalnihmesta = InputBox(Prompt:="Unesi broj decimalnih mesta", Title:="Decimalna mesta")
    eIndex = Application.ActiveCell.Column
    eRowIndex = Application.ActiveSheet.Cells(Rows.count, eIndex).End(xlUp).Row
    Range(Cells(2, eIndex), Cells(eRowIndex, eIndex)).Select
    System = Application.UseSystemSeparators
     With Application
        .DecimalSeparator = ","
        .ThousandsSeparator = "."
        .UseSystemSeparators = False
    End With
      If System = True Then
            DecSep = Application.International(xlDecimalSeparator)
            ThousendSep = Application.International(xlThousandsSeparator) 'not used;for information only
      Else
            DecSep = Application.DecimalSeparator
            ThousendSep = Application.ThousandsSeparator 'not used;for information only
      End If
 
  
   For Each z In Selection
  
  If brojdecimalnihmesta = 0 Then
        z.Value = FormatNumber(z.Value, brojdecimalnihmesta, , , vbTrue)
    ElseIf brojdecimalnihmesta = 1 Then
        z.Value = FormatNumber(z.Value, brojdecimalnihmesta, , , vbTrue)
    ElseIf brojdecimalnihmesta = 2 Then
        z.Value = FormatNumber(z.Value, brojdecimalnihmesta, , , vbTrue)
    ElseIf brojdecimalnihmesta = 3 Then
        z.Value = FormatNumber(z.Value, brojdecimalnihmesta, , , vbTrue)
    ElseIf brojdecimalnihmesta = 4 Then
        z.Value = FormatNumber(z.Value, brojdecimalnihmesta, , , vbTrue)
    ElseIf brojdecimalnihmesta = 5 Then
        z.Value = FormatNumber(z.Value, brojdecimalnihmesta, , , vbTrue)
    End If
  
   Next
    With Selection
  
    .HorizontalAlignment = xlRight
   ' .NumberFormat = "###,###,###,###0.00"
    
   End With
  
   Exit Sub
 End If

when I apply my macro each number for example 34563,9843 is displayed in the format 34,563.98 when I enter the number of decimal places 3 or 4 or 5. when I select the number of decimal places 1 the display in excel is 34,563.90. the display after the separator and decimals is fine with the menu, but why doesn't it display decimal places larger than 2.
I have the same problem with the percentage format.
I noticed when I entered the number of decimal places. This number actually rounds to that number of decimal places, and a always shows 2 decimal places