Bill Tindall, E.Tn.
"shrink each time it dries, but spring back less "
Well documented phenomena. In the typical KD process the wood is dried below the final target moisture content, then steamed back to 7%. The steaming is to relax drying stress. But the other benefit is that the wood becomes less responsive to humidity changes. I have heard loss of volatiles as an explanation but I believe there are significant chemical changes going on too.