At the beginning I want to write, that You made a nice and simple plugin. Of course if plugin doesn't have any error, it's probably "Hello world!" plugin :)
I set to my user (using ID) limit of 3 posts (I choose "any" state). Everything works great until my user sends few posts to trash.
For example, my user reached allowed limit and decided to move one post to trash. He or She has still 3 posts (2 published and 1 in a trash). If count of posts not in a trash is less than 3, Your plugin allows to add a new one. After adding a fourth post, my user can recover post from trash and that's the way He or She can have more than allowed limit. The problem probably is placed in "any" state. It's not getting "trash" posts.
Could You be so kind and write me down, how to fix it?