For ACE and ACI emanifest one shipment is usually considered as one pick up and one drop off. If you pick up at one location and have two drops CBP and CBSA consider you as having two shipments. Sometimes a customs broker will try to consolidate two or more drops into one shipment. Often then, upon examination of the accompanying paper work, the border services officer will reject the shipment. You will then need to re-do your emanifest showing the total number of actual shipments. This results in significant delays and added cost.