This is from NCL's web site. The end of the paragraph answers your question ...
The choice is yours. With Freestyle Cruising, you travel a world of dining options all in one week. From elegant French bistros and Italian trattorias to sushi and tapas bars, and more, there’s a different dining option for almost every night of your cruise. With up to 10 different restaurants, each featuring a diverse an ever-changing menu, you’ll always find exactly what you’re in the mood for. And there are no fixed seatings. Imagine restaurants open from 5:30 pm to midnight so that you can choose from an early dinner before the show or a later romantic dinner for the two of you. And of course there’s always the option of 24-hour room service. You’re free to dine where, when and with whom you choose. Just as it should be on your vacation.