Primary warehouses are telling me I can’t release a single/back-to-back on the 8000 CCN. What is the regulation?

Primary warehouses are telling me I can’t release a single/back-to-back on the 8000 CCN. What is the regulation?

As per paragraphs 115 and 116 of the updated Freight Forwarder Pre-arrival and Reporting Requirements Memorandum D3-3-1 http://www.cbsa-asfc.gc.ca/publications/dm-md/d3/d3-3-1-eng.html, single shipments that are destined to the same warehouse as the primary cargo, and are in good standing, will be arrived by the conveyance arrival certification message (CACM) and released. Single shipments that are destined to the same warehouse as the primary cargo, but do not have a release on file in good standing, or require examination must be arrived by the primary warehouse using the WACM.