When fully extended the bar end shifters add about 2 1/2" to your handlebar drops. That's quite a bit. The last time that I redid my bike I cut a bit off my handlebar ends but I didn't take the whole 2 1/2". I think that I took about half that, maybe even a little less.

The bottom line is that I'd forgotten about cutting the bars until your post. It's been one of those modifications that "disappears" when I ride so it must have been the right thing to do.