The thought behind the Kaplan Method is that you only want to read the stimulus once. If you read the text, then look at the question stem and realize there was a detail you needed to pay attention to but accidentally skimmed, you end up wasting time reading the prompt a second time. Needless to say, having taught that method for five years, I buy into it

I can't speak for the effectiveness of the Powerscore CR method; I'm sure it works for at least some people, if it's in their books. What I can speak for is the dangers of mixing methods. If you've been training with Kaplan methods, then the Kaplan method should at this point be a reflex. It's hard enough trying to retrain your initial habits to develop an instinct towards the Kaplan method; at this point, trying to eliminate
those habits is likely as not to drop your verbal score even further.
In the mean time, you seem to be having trouble with Kaplan CR. Can you tell me what exactly is tripping you up? I'd be happy to give you some advice to put that last bit of polish on our techniques and strategies.