Dim dt1 as DateTime = DateTime.ParseExact("12:00", "HH:mm", nothing)
Dim dt2 as DateTime = DateTime.ParseExact("14:00", "HH:mm", nothing)
Dim ts as TimeSpan = TimeSpan.Parse("0:40")
 
Dim ts1 as TimeSpan = (dt2 - dt1).Add(ts)
Dim ts2 as TimeSpan = (dt2 - dt1).Subtract(ts)