Smashwords & KDP & …? Multiple Listings?

Hi

I’m slightly confused about publishing with Smashwords.  Smashwords seems to publish your work to all the major sellers of e-books for all major formats.  However, you (Catherine) say that you will need to produce one version for Smashwords Edition and one for  Kindle Edition.  I actually want to publish direct with Amazon KDP anyway but if I then publish with Smashwords in order to cover all the rest, does that not mean there will be two versions on Amazon KDP.  Same story if you publish a version direct to the Apple i-book store.

Can someone clarify please?