Slide In (Maybe) Not Working...

Perhaps I do not understand how it works, or perhaps it is not working...

I have a Slide In that I want to appear on a specific post.

I have checked "Not in pool" and then on the post I want it to show on I have selected it in the "Slide-In Message Override"...
Problem: It doesn't appear when you visit the post...

Am I misunderstanding how this should work - or is it not working correctly?

I do have a slide-in "in the pool" and set for the home page and it works fine...

Here's the url for post where it is mis-behaving:
http://www.crmsuccessplans.com/the-top-7-reasons-marilyn-monroe-would-have-loved-act-crm/