Of every ten D&D disputes we have looked at while designing this product, the single largest category is not a disagreement about dates. It is a container rated on the carrier's public tariff when a service contract with better terms existed.
How it happens
A shipper or NVOCC negotiates a service contract: seven days free at destination instead of the tariff's three, a lower per-diem, combined rather than separate D&D. The contract is filed. The bookings are made — sometimes under the contract number, sometimes not. The carrier's billing engine rates the container when the clock runs out, and if the booking did not carry the contract reference cleanly, or the contract's lane definition did not quite match the port, it falls back to the tariff.
Nobody on the carrier side is doing anything wrong, and nobody on your side sees the contract at the moment the invoice arrives. The clerk sees "3 days free, 5 days billed" and it looks right.
Catching it
The check is mechanical once the contract is indexed: for each invoice line, find the contract that governs the booking (carrier, shipper, lane, container type, date within validity), read its free time and rates, recompute, compare. Where the invoice's implied terms match the tariff rather than the contract, the line is flagged as tariff-rated with the clause quoted.
On a monthly statement of two hundred lines this is a minute of computation. By hand it is a day, which is why it is not done.
Fixing it upstream
The dispute recovers the money; the pattern tells you something more useful. If 60 % of a carrier's over-billing is tariff-rating, your contract reference is not reaching their billing system — a conversation with the carrier's account manager about booking references, not a dispute. The recovery report by cause exists for that conversation.
The number
We are careful not to invent statistics on this site. What we can say is that in every forwarder and audit desk we have spoken to while designing D&D Pilot, tariff-rating was the first or second cause named, and none of them had a systematic check for it. That gap is the product.