The vessel does not decide it, the string does. Ask for the service name on the confirmation, then read that service's rotation on the line's schedule: it shows the way round without anyone typing the word canal.
Their terms allow any route and promise no arrival time, so the window is yours unless the sale contract says otherwise.
Early is not free in fruit. Free time runs from discharge, not from your eta: the box sits, the plug bills, the cold store sold that week. Mine flipped mid season. The slot did not move.
Camila's rotation reading is how I would find it. Get it in writing too, because the paper needs it.
The boxes go on the vessel; the documents go by courier and through the banks, which does not speed up when the vessel does. A vessel ahead of its own documents means no original bill of lading at discharge, so somebody signs an indemnity to release them. Under a credit the presentation period runs from shipment, not arrival, so the time lost is yours.
The transhipment port matters as much as cape or canal. On a preferential set the route is declared, and the importer must prove the goods were not handled in transit. How an officer reads a route that did not happen, I am not sure. Our auditor asked for that confirmation last time, so now it is filed.
camila, the window is mine. always was. i took a confirmation eta for a commitment.
service name and transhipment port in writing, every booking, since they can swing back the long way voyage by voyage. my dates come off my terms, not the line's eta.
no plug, no cold store in homeware. the slot still does not move. thu ha, the originals never crossed my mind.
same boat, transpacific side. we quit booking the dc off the booking eta. slot gets booked off the arrival notice, and an early box just sits at the terminal on free time. cheaper than fighting the warehouse.