Mind you, Bilbo is knocked out for almost all of that battle, and the douchey director Peter F. Jackson couldn't possibly let his ego and an enormous CGI budget not go to his head, so of course he just starts making shit up willy-nilly.
I just want to remember the original Hobbit I read in the 70's and not dwell on the money makers of sequels and re-runs. Tolkien would roll over in his grave if he knew what the media has done to his work.
A pity this last installment is the least successful of all the tolkien flicks. Thorin is the only good thing about it (and Smaug, but he exists only before the opening credits, so...). I bet Jackson could've made a really good "Hobbit" in one part. As a story, Bilbo and Smaug should've been the crux.
Thank the stars in heaven, we have you to enlighten us about fantasy fiction!