I don't think the PR CAT's are a reliable gauge of your score because their questions are so simple. Your margin of error is narrow because you're basically dealing only with 500 and 600 level questions. I get similar results as you do on my PR CAT's. Here are my latest verbal scores:
As you can see there really isn't a convincing correlation between the number of questions you answer incorrectly and your eventual verbal score. The only advice I can give you is to utilize the PR CAT's to train your consistency, and always think in the back of your head that one wrong answer can potentially lower your score 2-3 whole points. Analyze your mistakes and pinpoint what you did wrong. Then go back and take the GMATPrep, which should paint a clearer picture of where you stand.
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