Board Thread:Naruto Discussions/@comment-38792431-20200226192508/@comment-9782468-20200226202233

A jutsu's rank doesn't denote its power or its offensive capabilities. It denotes its difficulty.

The difference between them is simply Kakashi has developed it further. Same principles. They have separate pages in the databook and separate ranks as well as you mentioned.

Not only that, Sasuke makes a point to correct Deidara during their fight; Deidara calls Sasuke's jutsu "Raikiri," but Sasuke corrects him saying it's only "Chidori.