Thanks for the tag!!
It's impossible to answer this question with certainty, because AAMC has said two different things. The document you have linked does indeed say that the number of scored questions hasn't changed. AAMC has also published
this, which implies that it has in fact changed, without explicitly saying so:
"Students will still be tested on all four sections of the exam and will be responsible for demonstrating the same knowledge and skills at the same levels of difficulty as on the full-length exam. While there is a small reduction in the number of test questions in each test section, the shortened exam maintains the same format and tests the same things as the full-length test. Students will receive the same scores on the shortened exam as they do on the full-length exam. They will receive five scores: one from each of the four sections and one combined total score. Additionally, scores from the shortened exam have the same precision and are reported with the same confidence bands as scores from the full-length exam. Admissions officers will know which students took the shortened exam."
All we know for sure is the test has 38 fewer questions than a full length exam, which does seem like it would be a lot of field test questions. We also know, anecdotally through reddit reports, that people are seeing a much wider variance between their FL average and their actual score (both up and down) than in the past, which would be consistent with fewer questions being scored on the shortened exam.
I don't work for AAMC, so I honestly don't have any greater insight into the issue than this. Also, it doesn't really matter, since there is nothing you can do to prepare differently one or the other. It is what it is, and there is nothing you can do about it other than not take the test until January, so you really do have to just go with the flow, and realize that it's totally luck of the draw whether the change will help or hurt you. And, of course, if the number of scored questions is exactly the same (which just seems unlikely), the change only helps, since it allows you to complete the test sooner and allows you to avoid being a guinea pig for future examinees with no benefit for you.