VBA Function Procedure

Public Function DISKON(totalBelanja As Long, Optional persen As Currency = True) As Currency
    If persen Then
        If totalBelanja < 100000 Then
            DISKON = 0
        ElseIf totalBelanja <= 150000 Then
            DISKON = 0.05
        ElseIf totalBelanja <= 200000 Then
            DISKON = 0.1
        Else
            DISKON = 0.15
        End If
    Else
        If totalBelanja < 100000 Then
            DISKON = 0
        ElseIf totalBelanja <= 150000 Then
            DISKON = 0.05 * totalBelanja
        ElseIf totalBelanja <= 200000 Then
            DISKON = 0.1 * totalBelanja
        Else
            DISKON = 0.15 * totalBelanja
        End If
    End If
End Function

Public Function LULUS(nilai As Currency) As String
    If nilai >= 80 Then
        LULUS = "Lulus"
    Else
        LULUS = "Tidak Lulus"
    End If
End Function