Aplikasi billing sederhana dengan visual basic 6.0

langsung saja ini scirpnya :
Dim Start1 As Date, Stop1 As Date
Dim Harga As Integer, Biaya As Integer
Function DateDiffX(dStart As Date, dEnd As Date, Optional bDetailed As Boolean) As Variant
    Dim TotalDays
    Dim Years, Months, Days, hours, minutes, seconds

    If bDetailed Then
        TotalDays = dEnd - dStart
        hours = Hour(dEnd - dStart)
        minutes = Minute(dEnd - dStart)
        seconds = Second(dEnd - dStart)
       
        If hours < 10 Then
            hours = "0" & hours
        ElseIf hours > 9 Then
            hours = hours
        End If
        If minutes < 10 Then
            minutes = "0" & minutes
        ElseIf minutes > 9 Then
            minutes = minutes
        End If
        If seconds < 10 Then
            seconds = "0" & seconds
        ElseIf seconds > 9 Then
            seconds = seconds
        End If
        DateDiffX = hours & ":" & minutes & ":" & seconds
        Exit Function
    End If
  
End Function

Private Sub Command1_Click()
If Command1.Caption = "Mulai" Then
    Command1.Caption = "Stop"
    Timer1.Enabled = True
    lblMulai = ": " & Format(Time, "hh:mm:ss")
ElseIf Command1.Caption = "Stop" Then
    Command1.Caption = "Mulai"
    Timer1.Enabled = False
    lblSkrg = ": " & Format(Time, "hh:mm:ss")
End If
End Sub

Private Sub Command2_Click()
Unload Me
End Sub

Private Sub Form_Load()
Start1 = Format(Time, "hh:mm:ss")
Harga = 10
End Sub

Private Sub Timer1_Timer()
Stop1 = Format(Time, "hh:mm:ss")
lblSkrg = ": " & Format(Time, "hh:mm:ss")
lblDurasi = ": " & DateDiffX(Start1, Stop1, True)
Timer1.Tag = Biaya + Harga
lblBiaya = ": Rp. " & Timer1.Tag
Biaya = Timer1.Tag
End Sub