I was also wondering about that. The cover of the boxed set says DTS, while the cover of the disc-only version does not. However, the product description of the disc-only version inserts DTS on the very last line. Both, however, say Extended Edition.
With those descriptions, I'm guessing the actual disc contents will be the same; they just have different covers, like what happened with the local Constantine Deluxe/Special Edition releases.