Thx for the review, I guess, Will check it out.
That make sense, it's in contradiction with what was stated before, but it would not be the first retcon of Kishimoto.
In fact, the fourth data book (never translated officially) has a page dedicated to ying yang release, which supports my interpretation.
I hope this helped because I actually spent a lot of research on this kind of stuff for this fanfic.
It did help explain this indeed ^^