Board Thread:Naruto Discussions/@comment-25027221-20150427015318/@comment-1018594-20150427020752

I'd say that they probably had an official base somewhere (most likely Pain's Tower, but it very rarely saw all of them together. At the end of Part I it was said that it was the first time they were all together in years, I think.

The databooks aren't necessarily the best source for information on things like this, which are mentioned in passing. They're more for logistic and character information than anything else. They've been known to partially or sometimes completely contradict the manga on some issues.