Yeah that's how I interpreted, just kinda sad that a really nice armor focused option doesn't work with an armor focused archetype to make a hyper focused armor character. Since armor is kinda lackluster mid-late game.
edit: minus a few things where I feel stacking should have been relaxed to let a character who dedicates themselves to a rather sub-optimal route become mega badass at it this book has been rather ok. It's got some cool things in here I know my table will definitely use, but I'm getting pretty tired of seeing "This DR option doesn't stack with any similar DR thing ever!" just feels unnecessary to prevent nice things from becoming nicer.