A carrier’s insurance is not a fact about your load
Most systems attach documents to shipments. That single modelling choice is why everyone re-uploads the same certificate forty times a year.
Attach a document to a shipment and you have quietly asserted that the document is about the shipment. For a CMR that is true. For a carrier’s liability insurance, a driver’s licence or a truck’s inspection certificate it is plainly false — those are facts about the carrier, the driver and the truck, and they stay true across every load until they expire.
The cost of the wrong owner
When the model is wrong, the work shows up as re-entry. The same certificate gets uploaded once per trip, the folder fills with forty copies of one PDF, and nobody can answer the only question that matters — is this carrier’s insurance valid today — without opening the most recent trip and hoping whoever built it attached the current version.
Renewal is a new row
The second half of getting this right is refusing to update in place. When a certificate is renewed, the new one is added and the old one stays. Overwriting would make the current state correct and the history unanswerable, and history is exactly what you need when a claim arrives about a load that ran in March.