You can see the consequences it might have for an exporter. He wants to send his product to his client, but he has no control over the time when his railcar will be assembled to the train. It might result in costs over which he has no control.
Some adjustment should be made so that the exporter might declare as his export date the day when the product is loaded in the railcar. It should be possible to find a way to reflect the real date of the export.