At the moment concert statistics and top fan pages do not include performers or bands seen at festivals. At the moment your attendance statistics assume you have seen every single performer for each listing. While this is reasonably accurate for concerts, it is definately not so for festivals where everyone moves from stage to stage.
Specifying which bands you've seen at festivals (as well as separating listings per stage) is a planned feature but not currently available.
For now you should just add the entire festival to your calendar and is soon as the more advanced selection is available you will be notified so you can update your profile and include additional performances to your statistics.