Hi RafalD,
I’m glad you reached out, and I’m happy to help. I see a few things to consider here:
First, the comparison you are trying to make (OG scoring versus MBA.com test scoring) is not an apples to apples comparison. Remember, since the OG does not contain every type of question from every topic, it’s quite possible that you still have a variety of weaknesses that you have to address in order to improve your GMAT score.
Furthermore, since you are at a V28, it’s clear that you lack the verbal fundamentals you need for a high score, right? So, rather than relying only on practice to improve your verbal skills, you may consider using a course that provides a structured and linear study plan, so you can start with the foundations of GMAT verbal and progress to more advanced topics. By taking such a methodical and gradual approach, you ensure that you fill in gaps in your knowledge and that no stone is left unturned.
Finally, in answer to your questions about how to improve your test performance and what factors other than knowledge may influence your results, I can say that GMAT verbal is not as much a test of knowledge as it is a test of skill in noticing key details in questions and answer choices and in carefully using logic to arrive at correct answers. So, it could be that you have picked up enough knowledge to correctly answer most OG questions but have not developed your skills enough to correctly answer tricky questions with new twists, such as those that appeared on the test you took.
If you’d like any further advice on how to improve your verbal skills, feel free to reach out. You also may find it helpful to read this article about
how to score a 700+ on the GMAT.