If you are referring to the source on another board who said that she was told that she would be able to do it, then yes, she is very, very reliable and I would trust her information. CMs with different, contradicting info is nothing new at Disney. The CMs on the phone lines have different information than the CMs in the ticket booths. And the leads in the booths should have more info than the newer CMs at the windows. When the source on the other board says that she no longer is able to add a day, then I would worry.