No, as ever it's a bit more complex than that! The box set version is a remix, it was reassembled from the multitrack and it differs in several ways. The most common complaint is the echo (which had to be re-added) is out of time compared to the original, plus there are other issues where things drop in / out very slightly differently. We need to think of the box as a very different thing than a remaster, it is in effect another Bitches Brew. I've not actually heard it so I can't pass any comment, all I know is it is rather controversial as it does alter history to some degree.
If you want a digital Bitches Brew that at least shares the same mix as your Columbia 2-eye the best is apparently a Japanese issue from quite a while ago (late 80s or early-90s IIRC), I can't recall which one, but the details are hidden somewhere on one of many hundred plus page threads over on Steve Hoffman's forum. Luckily for me this mastering was selected for the remarkably well-compiled
71xCD Complete Columbia Albums box (they really did pick the best masters rather than the most recent), and I think it sounds superb, but I've not compared it to much (only a very different quadrophonic vinyl mix). The lucky thing for everyone else is that it's also the master selected for
Perfect Miles Davis Collection box. This box is effectively a subset of the 71xCD set and is one of the great bargains in the history of recorded music. Everyone really should buy it immediately (yes, right now! It is but a click away!). You'd likely pay a lot more for the original Japanese CD of Bitches Brew!