Nosrat’s distinction: salt added early fundamentally changes the structure of food (draws out moisture, denatures proteins, seasons through); salt added late just hits the surface. They are different acts.
Applied to masa: salting the masa dough rather than the finished tortilla changes the flavour entirely — it’s distributed throughout rather than sitting on top. Tested both. The salted dough tortilla tasted more cohesive; the surface-salted one tasted patchy.
Rule to remember: if you’re not tasting at every stage, you’re seasoning blind. Salt before the pan, taste after, adjust before serving.