If you look closely, you'll see three important things: 1) These armors have only a 5% arcane spell failure chance2) These armors have no Armor Check Penalty3) These armors have a max DEX bonus of 8
mithril reinforced clothing ... lvl reqs of 22... has a DR of 5/- to Bludgeoning, Slashing and Piercing, no AC check penalty and does not limited ones AC bonus.