I can see the "commit to it completely for 6 months" thing working on a lot of people who are just beaten down but don't know TTATT. The way cults work is to get you to participate in spite of your better judgement and that causes cognitive dissonance, which forces you to have a better view of the cult (your participating in cult activities is contrary to your negative feelings about the cult so you either have to change your actions or your feeling about the cult - if you've committed to trying it for 6 months, most likely it will be the latter).
What I'm wondering is if this 6 month trial period is an institutionalized thing. Is it a recommended tactic in the elder's manual or at the elder's school, or is it just a fluke that a couple elders hit upon the same thing? It always interests me to see what bits of the cult indoctrination and mind control come from the top. It seems like most of it does, but there have definitely been a few cases that I've seen where it seems like a few elders or a CO have happened upon some particularly unique method of controlling people that isn't used by the organization as a whole.