Board Thread:Naruto Discussions/@comment-34436445-20180524144523/@comment-25122992-20180611185809

Nowhere does it say that Susanoo exists in alternate dimension. Plus, while witnessing Madara's Perfect Susanoo, Onoki stated that its chakra got stabilised, which means that Susanoo is still made out of regular chakra.

Just a note, databooks use a lot of figures of speech, so some of their statements shouldn't be taken per word. Also, most of Susanoo's intro in the third databook refers exclusively to Itachi's version of Susanoo.