Help with Hamelman elaboration instructions

I'm confused about Hamelman's levain method in Bread. In the formulas, he routinely has you mix up the final levain from an active starter of 20% weight (5% for rye), fermenting for 12-16 hours at 75f. ( I think this is the "Detmolder one-stage" method?) 

But in his technical instructions on  p148 , Hamelman instructs to build the levain over two and three elaborations, starting with a small amount and growing by a factor of two or three at a time until you get the final levain.

 Weird thing is none of his formulas ( except perhaps the miche) use elaborations! Granted, the one-stage method has worked well for me, even using an old chef sitting in the fridge as the 20%.  

So which is it? And I'm wondering how the rising and sourness would be affected between the two methods?