Hi prernasrk,
CR and RC prompts, like almost all GMAT prompts, are about patterns and repeatable steps. You might find an individual RC passage to be short or long, easy or hard, simple or complex.... but you should deal with it in the exact same way EVERY time. The Verbal side of the GMAT requires almost no imagination or cleverness on your part - it requires a cold, methodical approach. RC prompts require the same general approach regardless of the details because RC prompts are based on the same handful of question types.
CR prompts test a slightly wider range of thinking, but they too are based on patterns, common themes (and even common wrong answers). You should never "wing it" on a CR prompt. Identify the type of question that you're facing, then follow the proper steps to beat it.
From what you're described, I don't think that you were really focused on learning, memorizing and practicing the "steps" for RC or CR. With a V23 on your GMAT, you're also losing out on some SC points, so you might not know all of the grammar rules that are required. Furthermore, you could very easily be too fatigued to do the work correctly and the way with which you choose to handle the Verbal section might be leading to some pacing problems.
You still have not provided much information about how you specifically scored on each your CATs nor how you "took" each CAT (what time of day, did you skip sections, etc.). Those factors, if they vary from your Official GMAT, can help to explain the difference in scores. In addition, a 580 could very easily have been a 610 (GMAC has stated that, statistically speaking, your Official GMAT score is within +-29 points of actual ability), so your Official Score sounds like it might be right in line with how you performed on your practice.
GMAT assassins aren't born, they're made,
Rich
