IR is based on the # correct, but there is also a small adjustment based on the overall difficulty rating of that particular IR section.
Also, note that the # correct doesn't directly translate into your score. There are 12 questions in an IR section but the score range is 1 to 8.
Next, how to improve. You mention "especially" wanting to improve the verbal. I just want to make sure you realize that your verbal score is already the higher of the two scores.
V36 is 80th percentile. Q47 is 70th percentile. Since you want to raise your score overall, it's a good idea to try to improve both, of course.
V38 is 84th percentile, so there is not a big difference between 36 and 38. That is definitely within the standard deviation of this kind of test.
In order to figure out how to improve, we need to dig into the data from your practice CATs.
First, read these two articles:
https://www.manhattangmat.com/blog/inde ... lly-tests/http://www.manhattangmat.com/blog/index ... -the-gmat/Then, use the below to analyze your most recent MGMAT CAT (this should take you a minimum of 1 hour - dig deep!):
https://www.manhattangmat.com/blog/inde ... ts-part-1/Figure out your strengths and weaknesses as well as what you think you should do based on that analysis. Then come back here and tell us; we'll tell you whether we agree and advise you further. (Note: do share an analysis with us, not just the raw data. Part of getting better is developing your ability to analyze your results - figure out what they mean and what you think you should do about them!)
Also, let us know what you did to prepare the first time around, as well as what materials you used / still have, and what you think you may need to do differently this time around (based on the above analysis).