There are a lot of logistics that go into provisioning the ship, especially for a world cruise. This isn't a seven day weekly run to the Caribbean. It's more than making a schedule, especially when doing heavy storing. A lot of these items will not be reprovisioned until the ship returns to the States in May. I can almost guarantee you she will sail late on May 12th as well. You can only load the palettes so fast, and once onboard, space is very limited and the pallets have to be fork lifted to their designated area. The oncoming stores have to be inventoried, and are also subject to inspection by Customs and canines. The ship chandler is in charge of the scheduled deliveries. Dozens of trucks line up continually all day long, and it is a coordinated effort. It is a long, exhausting day, and you have hundreds of deliveries, you can only go so fast.

xrvlcruiser is correct. Crew change, disembarkation, customs and clearance all play a part in the puzzle. Luggage also has a huge impact, especially the amount of luggage and specialty items for the world cruise guests. Some even send their lazy boy chairs and other favorite items. Several years ago the Voyager loaded a container to hold all of the world cruiser's luggage during the voyage. They decided to keep it. It is on the bow of the ship, starboard side, and they painted it royal blue.