Userform Time Drop down Calculation

Private Sub TimeDone_Change()

If Me.TimeDone.Value = "" Then Exit Sub

start_time = TimeValue(Me.ComboBox1)
end_time = TimeValue(Me.TimeDone)

Duration = Abs((end_time - start_time) - (start_time > end_time)) * 24

start_break = TimeValue("1:00:00 PM")
end_break = TimeValue("2:00:00 PM")

'only dealing with 5 possibilities
'1   completely before break
If start_time < start_break And end_time <= start_break Then deduction = 0
'2   completely after break
If start_time >= end_break And end_time > end_break Then deduction = 0
'3   start before break and end during break
If start_time < start_break And end_time > start_break And end_time <= end_break Then
    deduction = (end_time - start_break) * 24
End If
'4   start before break and end after break
If start_time < start_break And end_time > end_break Then
    deduction = (end_break - start_break) * 24
End If
'5   start during break and ending after break
If start_time >= start_break And start_time < end_break Then
    deduction = (end_break - start_time) * 24
End If
'6  start and end within break (less than break hour)
'7  start and end within break (more than 23 hours)

MsgBox Format(Duration - deduction, "0.00") & "  hrs"

End Sub