Not the guy you replied too, and my memory is also fuzzy, but I always love how crazy and analog nes hardware was. Im like 70% sure that later in the nes lifespan they made it to where cartridges had more rom and could shuffle the data banks/tables around and that the nes could only process something like 32kb at a time I think? So they would just swap around the data sets depending on when they where needed.

Almost like one of those choose your own adventure books… Im probably horribly wrong in that summary and analogy though. It’s been years since I last got a refresher on nes tricks lol