My single biggest problem with these pieces is that Bernd Alois Zimmermann did all of this far better--and far more disturbingly--in the 1960s.
I'm not used to Lachenmann-as-pale-imitation-of-his-predecessors.
As far as I can see the experimentation with tonality happened as early as 2000, before he had released Grido and Schreiben in fact, with the Sakura variations.
I think the idea is that the listener will find himself reassessing his relation to mainstream music.
Concertini is interesting in this respect.