Melissa,
Certainly you are not the only person who has this question. I think I can offer some insight.
Unlike the other symbols on a Special Symbols page, the Nemeth Code terminator and the single-word switch indicator are Nemeth Code symbols. Everything else is a UEB symbol. (Okay, if the Special Symbols page includes a category of “Nemeth Horizontal Number Line Symbols” then not eeeverything else on that Special Symbols page is a UEB symbol, but you know what I mean.)
Although, it seems obvious that the "Nemeth Code terminator" is a Nemeth Code symbol, it might not be so obvious when you consider that the "opening Nemeth Code indicator" is a UEB symbol. So, on the Special Symbols page, we explicitly label the Nemeth Code terminator and the single-word switch indicator with the parenthetical "(Nemeth Code symbol)".
I hope that helps in some way!
–Kyle
P.S. The opening Nemeth Code indicator is a UEB symbol; it happens when UEB is the code in effect.