[JoeMac]

The difference is simple. Both add charges to the base rate. The difference is that a special service is something that must be done or the shipment cannot be transacted. For example, supposed that the customer resides on the second floor. There will be a problem with a carrier who is expecting someone on the first floor to take the shipment off of their trailer. So the special service is the added charge of delivering to the second floor and assumes that the carrier will carry out the service end of things.

If an order contains a special service it will exclude all rates that do not have the special service. The rate selected may have accessorials, say a fuel surcharge, but would never be selected unless it has the special service that matches the one on the order. I hope this helps.