Hi Bruce
Like you mentioned it would be related to go- around performance,however My FCOM 3 and QRH does not specifically mention "This will ensure the required go-around performance is achieved".
This doubt basically related to the relative angular deflection of flap/slat.
From Config 3 to 2,Slat does not move(and only flaps move).Wouldn.t that be preferable initially at high GW. vis a vis Config 3 to 1 where in both Flaps and Slat move.
Thanks