Issues with Calendar

[anon(5140585)]

Having some issues with the default Calendar, but before I go on and on, maybe an answer to a single question can resolve all issues. Does the default OS Birthday Calendar read Birthdays directly from my Contact List? I sync with Windows Live mail and contacts only, and display only the OS default Calendar and default Birthday Calendar. All contacts seem to be advanced a day on the Birthday Calendar, and Contacts List, but if I sign into my Live Account through the web on a PC, all birthdays are the day they should be.

Thanks!