Sometimes I bunch everything from 25mm to 32mm into “28mm” because I’m speaking in a greater context (for instance when I speak of the “foremost three” scales, i.e. 28s, 15s and 6s) and it would sound pedantic to say “25mm, 28mm, 30mm and 32mm”. This is much the same as when I (occasionally, but not consistently) bunch together 10mm and 12mm, or 15mm and 18mm, or 36mm, 40mm and 42mm. I just have to trust other people to understand that I’m modulating my degree of preciseness after the context, and not think I’m some sort of imbecile who genuinely believes true 25s and 32s are practically the same.
But anyway, to answer the question: if the context allows me to be more precise without making me sound pedantic, I use “heroic 28mm” and “30-32mm” interchangeably. Come to think of it, “heroic scale” would also suit well and I may just start using that term. People should probably be able to surmise that “heroic scale” with no actual measurement attached to it refers to heroic 28s as opposed to, for instance, heroic 15s.