Although your theory in why I would tell you that is quite off. I have not taken nor do I have plan to take the AT-SAT.
I also stated that because of several different reasons:
1. I know people that have purchased green book and still FAILED the test (and by failed I mean didn't even get a 70). I know others that did NOTHING to prepare and got in the 90s. Read on here a bit and you will find I am not applying and my husband is already in OKC. Why on EARTH would I want someone to do worse and/or not do good on that test? I honestly wish you the best and have no ill feelings towards you (I have not clue who you are...and I don't hold ill will to anyone really). I just don't think you need to waste your money and time.
2. This test was designed for RAW skills not for skills you train and train and train for a better score on. It is an APTITUDE test. I know everyone studies for it but my guess is that most of the time it is wasted. I would love to have the money and ability to actually test that theory! I have talked to MANY here in OKC, most did not studying for the AT-SAT, got in the 90's and are now here training.
4. If you really want help, work on hard analogy problems.
Example: Stain is to taint As Milk is to 1- ice; 2- silk; 3 - word
The answer would be silk...it is an "ilk" like milk. stain as an "ain" and so does taint.
You have about 30 seconds per analogy to figure it out.
Sorry for crappy analogy...had to think of it fast and off the top of my head. If I think of a better one or one that is closer to that which was on the test after asking some different people, I will post it instead!
5. Study reading gauges, basic math IN YOUR HEAD and angles. Studying those would help. All other things are honestly aptitude driven.