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11.10. Administrative records, such as customs documents, could provide useful information for modelling freight costs, as long as they include information about the commodity traded, the weight, the origin and destination and the mode of transport. Obviously, including such information also depends on whether it is available for the carrier involved. For example, administrative records may not have information on transport costs by type of merchandise. They also will not be helpful for the transport of cargo or passengers from one foreign country to another by a resident transporter, and administrative records might also be a weak source for measuring transactions related to auxiliary transport services, such as loading containers, storage or air traffic control.
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[1] The reason for this is that, in line with BPM6 recommendations (para 10.78), all freight costs up to the customs frontier of the economy of the exporter are shown as incurred by the exporter and all freight costs beyond the customs frontier of the exporter are shown as incurred by the importer (see chapter 14 and BPM6 Compilation Guide, para. 12.35).