Should/could Travel Disclosures be entered when the trip is booked, or only after completion of the trip?

You can log travel into the Coeus Travel Disclosure at the time of booking, and can then later update it if the trip is changed or canceled. If entering a trip in advance, when you get to the Certify page, Quit, do not certify. This will save all your entries to this point but will not submit it for review, leaving it available for future editing. Just be sure that the travel report is Certified and submitted within 30 days of completing the trip.