FACT: Manga, and Anime both support that Raikiri & Chidori are the same technique. Also supports that Raikiri was a name given to it after Kakashi (supposedly) cut lightning with it. Kakashi made the move himself and can call it whatever the hell he wants, and change the name for whatever reason he wants. If he wants to combine Raikiri and Senen Goroshii and call it the shocker, he can do that, its his move.

EVERYTHING ELSE: Speculation.

So, if Kishi doesn't release something with his signature seal on it then you can argue till you're blue in the face and still not have an answer...

CONCLUSION: Who cares...really?