Hi Saba,
It's been a several months since I last accessed the PrepCast quizzes so my memories of the drop-down selections are becoming fuzzy. However, what you mention sounds like what I was doing. Apart from not selecting the ITTO questions, I made sure not to include questions I'd already answered or from the exam simulator (to avoid encountering questions in the exam simulator that I would already have done), and then selected a random selection of questions, in order not to have ten or twenty questions in a row all on similar areas.
I don't know how much the content of the questions in the PrepCast platform (quiz/exam) has been modified over the years. I only used the platform for three months (Nov 2022-Jan 2023), so don't have experience of previous years. PMI's approach has changed, apparently, over the last few years, as shown by how its overall approach switched between PMBOK 6 and 7.
But my advice is not to get too bogged down in the whole knowledge areas/domains issue. Step back and look at the area of Project Management as an organic whole, then approach each quiz/exam question on its own merits, without thinking about whether it deals with a knowledge area, domain, process or whatever. The bottom line is that you want to prove to the examining body (PMI) that you are a competent and experienced project manager, which you can do by choosing the correct answers from the options for each question. It's a very limited method for assessing someone's real-world PM abilities, in my humble opinion, but that's standardized testing. (shrug)
Don't be overly concerned with your quiz scores at this stage. You are surely building up knowledge stores and understanding that reinforce your past experience. The brain is amazing at learning despite everything, so keep up the quizzing -- as well as looking up things that you find to be grey areas after the quizzes. To my knowledge, no one sees their average scores go down while practicing regularly.
One other thing I would add is that, based on my personal experience, the style and breadth of the questions in PrepCast are different to what one encounters in the PMI exam. I don't have documentary evidence to back this up, but I got the impression that the PrepCast questions cover far more ground than the PMI questions. While the PrepCast content involves a fair number of questions that require interpretation of graphical content and knowledge of formulae, my PMI exam in January was far more straightforward and almost entirely situational text-only questions, often to do with people skills and agile practices, and using barely any calculations or formulae.
This is good, in one way, in that PrepCast prepares candidates very thoroughly for every eventuality. As well as passing the certification exam, we want to improve our knowledge and understanding of project management. On the downside, I did find, personally, that the real PMI exam questions were generally vaguer and more difficult to pick a correct answer for. That meant that I found the real exam tougher than the PrepCast quizzes/exams that I'd been doing. But don't panic just yet! There's hope. Some of my course colleagues, who'd been finding the PrepCast questions harder to answer, actually found the real exam easier. This makes little sense, on the face of it. But I suspect that I wasn't at my best during the exam and therefore wasn't thinking quite as clearly as when I'd been preparing at home. They were perhaps on a good day, better rested, etc. (I still managed a good ATx3 score, so I did okay, despite the stressful exam experience.) These other colleagues all passed too, so if you're finding PrepCast quizzes challenging, you might also find the real exam less difficult.
Coming back to your question about PMI Study Hall, yes that's something to consider. It's PMI's own preparation platform, containing quizzes and mock exams written (I believe) by people who are involved in the writing of the real exam questions, along with other background/study content.
At the height of my exam preparation fever, I splashed out and paid for a subscription to their 'Essentials' package about three weeks before my exam date. However, I'll admit that I didn't use it much, since I was still working my way through the PrepCast quizzes and exams with which I was familiar.
If money and time are no issue, why not give it a try as a supplement? If your budget is tight, I wouldn't worry: plenty of people of people pass the PMP without even knowing that PMI Study Hall exists. My first experiences with it weren't positive and at that point in my preparation I was feeling that I was stretching myself too thinly. Therefore, I decided after a couple of days to concentrate on completing all of the available content from PrepCast and studying from my notes, so I barely accessed PMI Study Hall from then on.
Keep up the good work! Don't hesitate to get in touch if you have other questions or concerns.
