I believe that your conforms-to is incorrect. You need to have a super-type from the physical and the functional trees.
There are many outdated things in the documentation, please see my writeup about what parts you really need nowadays. For example you don't need the exportable types any more: http://www.cocoanetics.com/2012/09/fun-with-uti/
regarding import/export. It depends if this app owns the file type. If it does it should export it. If not it should import it. Of all the apps exporting a type IIRC the latest one wins. Any app that is able to read your type should import it. Also apps that state that they are able to work with UTIs upwards from yours can open the file. e.g. if your format conforms to plain text, then TextEdit can also open it.
Also with your experimenting you might have inadvertenly messed up your launch services UTI registry. My article mentions a way to clean it.