I would say that the scoring has to change day-to-day, depending on the test that you take. I only got two wrong on Organic and got a 23, got 1 wrong on G-Chem and got a 29, and got 3 wrong on Bio and got a 22. The only way to know how many you get wrong and how the scoring was done that day is to look at your TS score. This tells you exactly how many you got wrong total. From that you can backtrack to see how many you got wrong in each section and how the scoring was conducted that day.