The most common service consideration would involve the number of days to delivery, but mailers can also be interested in achieving delivery on a certain date or even in reducing the risk that the piece is lost in the mail.
Mailers can only deliver on certain days, no matter when the mail was sent.
mnli hypothesis: Mailers can only deliver on certain days, no matter when the mail was sent. premise: The most common service consideration would involve the number of days to delivery, but mailers can also be interested in achieving delivery on a certain date or even in reducing the risk that the piece is lost in the mail.