I don't know the answer to your question, but am wondering if getting home a few hours earlier is really worth all the extra stress and effort. You're going to be worrying your whole cruise about disembarkation day, with the stress level ratcheting up right up to that last night (which is always melancholy and somewhat stressful anyway). Different strokes and all that, but I'd just book the 3pm departure and enjoy a much more relaxing end to my vacation.