Updating service contract line item's end date

Question

Hi,
I am trying to extend the end date on a line item in a service contract via the DI and it is giving me the following error:  'Item's end date cannot be greater than contract's end date' and I don't understand why.
I retrieve the service contract object, change the header end date then find the line item  I need, update it with the same end date and then issue call the SC update method.  Here's my code:
    Try
             SC.Lines.SetCurrentLine(SerialNbrLineNumber)
             NewStartDate = LineEndDate
             'calculate new end date & extend service contract
             NewEndDate = NewStartDate.AddYears(Warranty_Duration)
            'never make the contract end date earlier than it had been
            SC.EndDate = IIf(NewEndDate > SC.EndDate, _
                                                         NewEndDate, _
                                                         SC.EndDate)
            'update service contract detail with new end date
             If NewEndDate > LineEndDate Then
                 SC.Lines.EndDate = NewEndDate
             End If
             If SC.Update() <> 0 Then
                rs.RtnCode = -1
                rs.RtnMessage = B1Comp.GetLastErrorDescription()
             End If
I did see something in the di help that mentions that B1 calcs an end date based on the "duration of coverage" field but I don't think I could use that because I might only change the end date for one line item. 
BTW I can do this in the application with no problem.
Thanks in advance for any assistance.

Answer 1

Known B1 bug.  Should have checked support first.  More info on note # 1026540