Well after a bath in hot water, the Addis relaxed a lot, as you can see in this picture of a sock I'm doing for Daughter #1. Also notice that the tensions of the foot part (again done flat) and leg/cuff now match. So I relaxed along with the Addis. I'm going to heed Yvonne's suggestion (to keep a couple of bead donuts on the loops); just have to go through my bead stash to find a couple (my bead stash, unlike my knitting stash, is currently in a state of utter chaos).
My new thought - now that I've mastered Magic Loop, I still have the 2nd socks to make to complete these 2 pairs. After that, no more flat-knit socks. How's that for progress? Before the winter break in late December, I wouldn't even attempt flat socks, now barely 2 months later I'm thinking about how to master Kory Stamper's 2 socks at once using Magic Loop. Nothing like having goals, even in knitting.