I am probably totally misunderstanding part of the question here, so let me apologize in advance if I am!
I just want new Kindle owners to understand when they purchase a book through Amazon and have it sent to their own Kindle, DRM or not, it can be read on ALL Amazon devices registered to that account. You can go back into your "Manage your kindle" page and have it sent to your Kindle4pc, or you can have it sent to your Kindle for Android, or whatever -- those are the two I happen to have. Or if you don't want to do that, in any of your other Kindle applications you can just open the archive and choose to have the book downloaded to that device. Again, if you're talking about something else entirely I apologize, but I'm just afraid that new owners might believe if they initially have the book sent to their Kindle they won't be able to access it on their PC or their phone.
Edit: I often download a book to my Kindle first and start reading it, then when I have the time I go back and open Kindle4PC and download it there. Then I add it to Calibre from My Kindle content folder, which works its magic because of the plugin. Yes, that leaves a DRM version on my kindle but I'm okay with that because I have the stripped one in calibre if I need it.