Shortening a bodice

Does anyone know--when you shorten a bodice, should you get rid of what you need to for the right length above or below the "shorten or lengthen here" line.  That's something that seems like it would matter.

I think you do it right at the line. So if you need to remove a 1/2" you'd cut the pattern on the line and overlap the edges 1/4", therefore removing an equal amount from each side. If that makes sense. At least, that was how I was taught. I could be wrong though, as we're a tall family and always have to add, not remove. LOL.

That makes so much more sense than what I was thinking. Thanks!