Thanks for verifying my guess.

That's already the case in my code; when I ask it for the notation for 581-EDO, the apotome complement of is never looked for, for this reason. But that's not the problem; the problem is that when it asks (rightfully) for the apotome complement of , it's giving an answer that is wrongfully influenced by the JI Ṗrecision Level notations' needs.Can't this be handled by a sufficiently general implementation of the same rule that you refer to parenthetically for when or is used as the half-apotome? Namely if a symbol represents the half-apotome in some EDO, it necessarily becomes its own apotome-complement in that notation, and so the usual apotome-complements of that symbol no longer apply and you revert to just flipping its accents.

I just spent my evening refactoring the @sagittal/system code base, realizing just how much of it assumed the JI Precision Level notations.