I'm not sure it's the port as much as it is the itinerary. A rarer itinerary is likely to have more higher level
Castaway Club people on it, which makes it harder for you to get a higher PAT/BG. Yes I know you're platinum, but if you're on a sailing full of Pearls and other Platinums, that'll make it harder. If you're on a sailing with lots of newbies, golds, and silvers, then you'll have an earlier crack at picking your PAT. I would imagine the 'bread and butter' 3/4 night itineraries on the Wish that leave out of Port Canaveral, for example, don't usually have a high number of higher CC level sailors. But, a rarer/longer itinerary might.