It does happen that the contacts and their units leave earlier than is posted because one of our packages went to Iraq and then came back to their base in Colorado. Fortunately, it was shelf-stable snacks that they could consume after they got back, and the contact was nice enough to write us and let us know what happened. I think he got a charge out of it.
That said, we normally time our last packages to ship about 6 weeks before the time listed on their web page for leaving there unless there is some kind of urgent request for something they are in dire need of, which is seldom. Hope this helps. That is what we have done for 3 years.
Gran