For Multiple containers documented under one cargo control document for importation, but will arriving at the warehouse at different times, when does the warehouse operator send the WACM?

For Multiple containers documented under one cargo control document for importation, but will arriving at the warehouse at different times, when does the warehouse operator send the WACM?

The warehouse operator will arrive the CCN when the first container physically arrives at the warehouse if all of the containers are physically in Canada.