A published number implies we can take your money and put you on the ground. On eight routes that is not always true. A park cap, a compliance category, a community that can withdraw consent, or a security picture that moves month to month: any one of those can close the week you asked for.
Galápagos berths are assigned to vessels, not to islands you pick off a list. Fernando de Noronha caps the main island and charges a daily tax that escalates with stay. Manu's Reserved Zone is allocated, not browsed. The Cuba programmes have to be structured inside an authorised category for US persons. Darién and Mosquitia run a live screen before anyone designs a day.
We would rather lose the inquiry than sell a permission that does not exist. If the month is wrong, or the corridor is closed, the first reply says so. Sometimes the answer is a different river, a later season, or no.