Hi Seeed, this is actually a pretty big problem for your customers. We're often working on very tight schedules, and while it is OK if production and shipping takes a long time, this time needs to be PREDICTABLE. For example, I ordered some fusion boards recently, and I have a prototype due on the 14th. I also am trying to write up a doctoral thesis, so planning my time is critical. I payed extra for FexEx shipping, and the product was initially predicted to arrive on the 2nd. Needless to say it has not arrived, and it is not predicted to arrive on the 5th, but I have no way of trusting this information. The issue is that the amount of time between when you generate tracking numbers and when you actually deliver packages to FedEx is completely unpredictable, so FedEx can't generate accurate tracking information. You need to ensure that the latency between when you mark an item as traceable, and when it is actually send to the shipping company, is constant and is well publicised. Otherwise you're customers will have a very hard time scheduling things and meeting deadlines, and it causes great problems. Again, it is not necessarily that the timing be fast, only that it be precise, consistent, and that customers are well informed of the expected delays in advance.