A carrier’s change does not appear in Dockflow at the same moment. If a carrier revises an ETA, Dockflow can show the previous value for a while.
This is visible as a lag of a few days in the worst case, and it explains differences where the carrier’s page is simply newer.
Example
A carrier changes an ETA this morning. Its own page shows the new date, and Dockflow still shows the previous one. Later the two match. If they still differ after several days, report it with the reference.