Hey Hawaiiandoc04,
I think you ARE overdoing it. I agree with Kry. It may be a better strategy to do a few full length tests in order to figure out which areas you are particularly weak in, and then spend alot of time focussing on bringing your understanding of those sections to a higher standard.
Most people I know get screwed by particular passages in certain sections; they get topics they are particularly weak in and thus get a lower score.
Another factor to consider (as mentioned by Kry): burnout.
I will use an analogy: A marathon runner does not run marathons everyday in order to train for a marthon that is a month away. Because they would bonk (ie. burnout/be too fatigued come test day). I believe this kind of thing can happen to people on tests, because they build up amounts of stress and fatigue.
There is one section that is the exception to all of this: Verbal.
I think the only way you get better at verbal is by trying out different strategies in timed test taking situations.
I hope I haven't confused you, if I have gimme a shout.
Cheers, and Good Luck
Silenthunder