Passive vs Active (cont) -- Assimil.

In my previous post, active vs passive, I mentioned the Assimil series of books.

I've was listening to one of their courses in the bath this morning and it strikes me that they are on the right track here -- in some languages.

Each lesson in the Assimil method teaches by dialogues, and you are expected to listen to each dialogue multiple times.  This is backed up by a translation exercise that in the course I was listening to (Le Catalan) was actually quite effective in rearranging the language taught into a new and fairly different form, but one that is still within the reader's comprehension.  Unfortunately the other book I've tried (Iniciación al Euskera) presents tasks that are impossible given the previously taught knowledge.

With all the listening, reading and relistening of the main dialogue, you're possibly only getting 5-10% of your time exposed to new comprehensible material.  The study I quoted said that even a 50-50 split of active vs passive was as effective as 100% active study.  Does this suggest that Assimil is not optimally efficient or that the fundamental differences between music and language are enough that this doesn't apply?