I noticed the same disconnect between the info you posted and the info posted by @Dunnedg just above yours. I mentioned this to the Seabourn consultant I booked with and she told me she was also aware of it and had reported it to the web team to be fixed. She assured me that jeans are fine in the Restaurant every night except Formal night, and it was clear that we were talking about standard jeans, not some designer fashion jeans.