Yeah, but if he calls himself "the Dragon" and later says "EU SUNT DRACUL", literally: I AM THE DRAGON, I would expect him to follow through and call himself Dracul.
Now. It is also entirely possible his name was retconned into Dracula, solely because people who just don't know the etymology would be confused and complain that they "got the name wrong", and ask why he isnt called Dracula. ESPECIALLy if they went with the Alucard=Dracula thing, where Alucard IS 'Dracula' hooo boy would that open a can of worms.
Another possibility is they just have him calling himself the Dragon and Dracul and just didnt bother to keep it that way, or their continuity checking department was out to lunch.
We'll see what the game calls him.
Another possibility, is one that has been suggested before- in that he calls himself Dracul, whereas people call him Dracula, since Satan would in their eyes, be the ultimate evil, "the Dragon", as it were, and this totally demonic evil guy is evil enough to be the Devil's son himself, and therefore gets called the son of the Devil. IOW, Son of the "Dragon."
Its an explanation I myself actually find pretty neat.