On a just completed 7-day cruise, Princess offered to upgrade to Plus for $60/person/day. I thought that meant that my cost would be $420/person or $840. I clicked the upgrade online which said the upgrade would be $907, which I declined. When onboard, I asked a passenger services rep why the $67 difference and he said, "I have no idea. Call Princess." Now, checking my next booked cruise of 12 days, which also offers an upgrade for $60/person/day, I expected the charge to be $720/person or $1440/couple. Trying to upgrade online, the charge is for $1673/couple or $233 extra. What could those extra charges possibly be for?