Just clarifying about the 5th person upgrade. For a seven night cruise, it is a charge of $175pp (less for 3 and 4 day cruises) plus the cost of the fifth person. In our case, our fifth person is an infant (so just taxes and port carges) and the total ended up being $931. Still a great deal for a seven night cruise in a Cat 4 room for five people! And the taxes and even tips are included for the four of us! We're very happy!
Incidentally, you are automatically assigned late seating for dinner, but can be put on a waitlist for early if you want. Too bad that they're doing that. I think it would hugely increase satisfaction to not make any distinction between those of us who book with a voucher versus a cash booking.