The Touring Plans service SENDS you a text if it finds an ADR time slot you want when it checks. That does not mean you will RECEIVE the text when the ADR time slot opens up. I tried it, and the text came through to me 4 hours after it was sent. I sent an email inquiring about the time lag, and they told me this happens with texts and I should google it.
Also keep in mind that it does not check constantly. Perhaps it searches every 20 minutes, or 15, or 25. I don't know exactly. But it is not always searching. So ADRs can open up and be filled while it is not searching for you. If you set up a search on the Touring Plans website, you can look at it and see when it last searched for you.
When I searched on my own, I saw two Be Our Guest ADR slots for lunch and 2 for dinner during the days I would be there. The only one the service found for me was the one for which the text arrived 4 hours late, and of course the ADR was gone by that time.