Board Thread:Consensus Track/@comment-4912646-20150519062854/@comment-6769189-20150519070906

At the time, Obito didn't have all the information. His knowledge of the events were incomplete.

The Tailed Beasts being with Hagoromo doesn't contradict that they were scattered, it just wasn't the first thing he did once he extracted and separated them.

As for where the statue was sealed, its possible that the moon was originally formed only using part of the Statue, while Hagoromo had a majority of it. However looking at the panels, we see the sun and moon symbols behind Ashura and Indra. It would seem Hagoromo and Hamura didn't create the moon until later. Black Zetsu also may have been referring to the Statue as the 10 Tails, considering the technicality, he wouldn't be wrong.