Is the left superscript minus sign in negative integers treated as a minus sign preceded by a space and therefore requiring the numeric indicator before the digit? or no numeric indicator? and if not, what is the reasoning, please? It always helps to understand the "why"!
Since the superscript indicator precedes a minus that is a left superscript, the negative integers in your example do NOT require a numeric indicator. This is because the minus is in fact not preceded by a space; it is preceded by an indicator.