Ah! I haven't read the most recent edition, but now that I'm glancing through it it looks like they streamlined a lot, especially re: opposed rolls, which might make it hard to write the kit in a way that works with both old and new material.
I think in earlier editions you could end up in a situation where you had half skill and you're making an opposed roll, which is why I wrote things the way I did---but just now I went back and re-read some of my copy of 6th ed and I understand it even less than before.
I do like your idea of scaling flat DR off of opponent skill, but I think it might result in a lot of high DRs with the way CoC tends to give its NPCs skills.
I'll rework the section. The new version should be up in a minute.