Not true!! Explora offers both 7 and 14 day itineraries all the time.
7 days is different that 14 days….IF you book it as the 14 day and not two 7’s. If you book it as two sevens, then you are correct, It’s two separate cruises and you would have to disembark and go through customs and re-embark.
Please see my previous post. We were NOT required to go through customs when we sailed last year, because we were on the 14 day itinerary.