Repetition

Hey all,

I'm working sequentially through one of Silman's intro-level CM courses (Endings, Openings, a Taste of the Middle).  It seems that several of the individual lessons are repeated 5-10 times.

I haven't looked through many other courses, but is this a very common deal with CM courses?  Is there something I'm missing?  Even though they're listed separately, as far as I can tell, they are all identical (although I have noticed comments like "See variation 2" or "refer back to variation 1" but other than them being called "different" variations they seem exactly the same).  The initial positions are the same and all the exact same moves yield the same results.