The file number being out of order doesn't mean anything. They're put on the certificates by the Printers themselves, then sent to whoever ordered them. From there they are subdivided and disbursed to the different agencies, hospitals or whatever, that need them, where they probably get subdivided even more within the Hospital itself. Even if the Hospital didn't subdivide them, there could be more than a down different reasons why the certificates may not be used in perfect sequence, especially if you're talking by only a few degrees of separation, which is the case here.
down = dozen