Label not changing

[kahaj]

I have this program that I thought was complete. Apparently not. The info in lasVegasTimeLabel.Text isn't changing when the info in dropOffDateTimePicker is manipulated.

Public Class shippingForm

   Private Sub clockTimer_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles clockTimer.Tick
      'print current time
      currentTimeLabel.Text = String.Format("{0:hh:mm:ss tt}", Date.Now)
   End Sub

   Private Sub shippingForm_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
      Dim currentTime As Date = Date.Now 'store current time 

      'set range of poss drop-off times
      dropOffDateTimePicker.MinDate = New Date(currentTime.Year, currentTime.Month, _
         currentTime.Day, 0, 0, 0)

      dropOffDateTimePicker.MaxDate = dropOffDateTimePicker.MinDate.AddDays(1)

      'display the delivery time
      DisplayDeliveryTime()
   End Sub

   Private Sub dropOffDateTimePicker_ValueChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles dropOffDateTimePicker.ValueChanged
      'display deliv time
      DisplayDeliveryTime()
   End Sub

   'calculates and displays deliv time
   Sub DisplayDeliveryTime()
      'print init deliv time
      Dim delivery As Date = DepartureTime()

      'add 3 hours to departure and display 
      delivery = delivery.AddHours(3)
      lasVegasTimeLabel.Text = delivery.ToLongDateString & " at " & delivery.ToShortDateString
   End Sub

   'return flight departure time for slected dorp-off time
   Function DepartureTime() As Date

      Dim currentDate As Date = Date.Now 'store cur date
      Dim departTime As Date  'store depart time

      'determine which flight teh shipment takes
      Select Case dropOffDateTimePicker.Value.Hour
         'seafood will be on noon flight
         Case 0 To 10
            departTime = New Date(currentDate.Year, currentDate.Month, currentDate.Day, _
               12, 0, 0)
            'seafood will be on tomorrow's noon flight
         Case 23
            currentDate = currentDate.AddDays(1)
            departTime = New Date(currentDate.Year, currentDate.Month, currentDate.Day, _
               12, 0, 0)
            'seafood will be on midnight flight
         Case Else
            currentDate = currentDate.AddDays(1)
            departTime = New Date(currentDate.Year, currentDate.Month, currentDate.Day, _
               0, 0, 0)
      End Select
      Return DepartureTime
   End Function
End Class ' ShippingTimeForm

What am I missing here?