It can be complex. Remember that this year the test is not the standard pencil & paper version, with every question worth the same, but the Computer Adaptive Test, where the first questions count the most.
As an example, your first question is going to be about a '50th percentile' question. Get it right and you get points for it, plus your next question is more valuable and harder, say, a '70th-percentile' question. If you get it wrong, you get no points, but your next question is easier, say a '40th-percentile' question. The system uses that to home in on where you should be ranked, with harder questions worth more when you get them right than easier questions, and a smaller range of movement as you answer the section.
So, a strong early response could establish you in a high range, quite possibly better than someone who answers more questions right, but who misses more early questions, and so gets lighter-value questions than you do.
Hope that makes sense.