I think it would be more like 3 or 4 wrong in bio and 2 wrong/at most 3 wrong in gen chem/orgo. It also has something to do with how hard each question you get right/wrong is.
I had 10 questions marked on the bio section, went back and got most of them but felt like i got 3 or 4 wrong and i got a 23 on bio. For orgo, I think I got one wrong, at most two to get a 25. For gen chem, I think I got one wrong, but the thing here was I had a really obscure question that I really think nobody would've gotten correct, but I got lucky with it, so I got a 29 because the one wrong question pulled me down from a perfect 30, but getting the really hard question right (just my theory) boosted me up to a 29.