OK makes sense, but I'll tell you what I'm seeing in my case in KOReader.

1. When I select a block of text, the "Add Note" button is grayed out, but Highlight (and the other options are active).

2. If I select Highlight, that works.

3. After it is highlighted, if I select the highlight and click "Edit", I can manually add some text within the body of the highlighted note text. That works too.

4. If I go to Evernote | Export all notes option, it does any highlighted material, but it does not export any text I added to those notes.

So at the moment: I do see that you can sort of hack the highlight feature to manually add a note into it, though the experience is not very good nor is the UI for accessing or displaying the note. And the Evernote export for me, only works on highlights. Notes/annotations for me is an important feature and something I really miss in KOReader at the moment.