I think that the (mod n) was added as an indication that this should happen, not as a mathematical notation. It's syntactically incorrect, which kind of gives it away.
Yes, I believe you're right. And in retrospect that makes total sense!
However, it's confusing given its placement right next to the equation. At any rate, it wouldn't hurt to make the documentation more clear in case any other developers are as unfamiliar with crypto concepts and byte management as I was. At least I learned a lot about bits/bytes/elliptic curves and everything else I tried in search of the answer.