I remember the info about an extra battle as coming from a quote from an interview with Jackson at a bookstore or something.
Hopefully, I've got it wrong.
Appreciate you getting back, but this is a little third-hand at this point! I won't get excited until I hear something a little more definite (though you've got me worried). Of course if, as suggested above, it is just a portrayal of a battle only described in the third person previously, it is ok with me.
I don't worry too much about an "extra" battle scene, or other rearrangements in the script to make something work out better in Jackson's mind. After the first film, I trust him with a little license.
Before seeing the first film, all of us were fretting over every rumored disastrous change in the story line. This fretting for me continued through the first viewing of the film. That first time through I frowned nervously at every slight alteration to this story that we know, quote and revere to near biblical detail.
But after that first viewing, the fingers crossed-"Lord I hope they do this right" viewing, most of us were willing to accept Jackson telling the story his way. Many things were moved, omitted, or added to FoTR, and the story was not lost.
When we view TTT for the first time, most of us will be nervous again, but should fear less, and know that Jackson is going to tell the sotry his way, and that even the changes are not necessarily counter to our "faith". I at least, will be giving this second film more benefit of the doubt when I notice changes, and my blood pressure may only go up because it is finally here, not because of a panic that something has been misquoted.