So, I finished the pieces of the grey sweater and thought vaguely about blocking them, and then looked at the back and the two fronts and thought--those all don't match.
The two fronts (it is a cardigan) are one length and the back is about two inches shorter.
So technically, the back WAS two inches shorter. What I did was pick up stitches along the bind off at the top and then just knit two more inches. Not sure what this means for the actual construction, but we'll see. Stay tuned.