I think they meant that a person needs to interpret “two numbers arranged vertically between parentheses” according to context, regardless of whether they’re si

I think they meant that a person needs to interpret “two numbers arranged vertically between parentheses” according to context, regardless of whether they’re sighted. Having more semantic information in that scenario would help the sighted just as much as the visually impaired—imagine hovering over an unfamiliar notation with your mouse and seeing it explained.