Probably because the standard textbook formulae are good enough to teach the curriculum to the students, and trying to teach something extra complex to a bunch of 14 year olds for a marginal object-level improvement isn’t worth it. Presumably potions class doesn’t teach you specific potions formulae, but rather teaches you the techniques and underlying concepts of potions so you can go to potions college with a firm grasp of the fundamentals.
Probably because the standard textbook formulae are good enough to teach the curriculum to the students, and trying to teach something extra complex to a bunch of 14 year olds for a marginal object-level improvement isn’t worth it. Presumably potions class doesn’t teach you specific potions formulae, but rather teaches you the techniques and underlying concepts of potions so you can go to potions college with a firm grasp of the fundamentals.