Hi
Ari777Official mocks are the most reliable ones as they are believed to be the closest to the actual GMAT. Hence, they are considered to be the best indicators of your performance.
Don't feel demotivated. You have come a long way and you know it all. You should consider to spend more time on analyzing the solutions of the questions from the topics in which you are weak. By analyzing I mean, go through each step of the solution, identify the exact step at which you made the mistake, compare your approach with the right one and then learn the right approach.
Coming to time management, taking extra time to solve questions is a symptom and not the disease itself. Let me elaborate.
There are 2 things that you do while solving questions - 1. You think about how to solve the question and 2. You solve the question. It's the first point that eats up unnecessary time. Now how do you tackle Point 1. Most people think the best solution is by solving additional questions. It does help but sadly is not the most effective solution because by just practising more questions you end repeating the same mistakes. The better solution is to learn the right logical methods to solve questions and then master these methods with additional practice.
This should help. All the best!
Feel free to reach out in case you need any help with your prep. Would be happy to help!