On Preface: Inquiry Versus Exposition

The famous passage from the preface of the German Edition is as follows:
"Of course the method of presentation must differ in form from that of inquiry. The latter has to appropriate the material in detail, to analyse its different forms of development, to trace out their inner connexion. Only after this work is done, can the actual movement be adequately described. If this is done successfully, if the life of the subject-matter is ideally reflected as in a mirror, then it may appear as if we had before us a mere a priori construction." p.28
In light with this passage how can we interpret the way Marx began its exposition in Volume 1. He seems to strangely starts with the discussion about commodity after years of years of reshuffling of Volume 1. Why? Could have been better if he had began the discussion in a different way?