Kev, I agree. I enjoy sticking to what HK describes and keeping it 'pure'
It does keep things simple.
The purpose of posing this question on this site is so that the true machinists here can give me their feedback as to how they see it. I mean... if accumulators are power sources with associated pressure points, the knees fall into this assumption.
I don't mean to say the yellow book is wrong - just a fun discussion!