I see your point but he has only seen Susano with SAsuke twice and that's it.. and even Itachi (a man touted to be one of the greatest geniuses ever (if not the greatest)) who Kakashi admitted to be inferior to in many ways (including doujutsu usage) couldn't use PS.. this chapter is just shit and wee all know it.. congrats to the fanbase that's been wanked cos this is the greatest ass pull in shonen manga history. Damn