It has confused several enigmatica 6 players thus far (EnigmaticaModpacks/Enigmatica6#4952 & EnigmaticaModpacks/Enigmatica6#4980), whilst the + feels fairly obvious the - could look like a list.

Maybe it would be a good idea to color them green and red respectively? One of the players confused by it suggested using the text version of both but there might not be enough room, i don't have any concrete ideas but it was worth sharing.

Yeah I personally would change + and - to "adds" and "removes" respectively, rather than using plus or minus, but Quezler is right that may not display correctly.

Adds and Removes end up being too long to fit for some cases. Might be well-to-do with some coloring, but people might get a bit confused (i.e. + spawn delay tends to be bad, but if all "+" are green, confusion).

This UI is quite tricky to get right.

Experimenting with it, I cannot comfortably use a color because it starts to implicitly convey "good vs bad" and some things (like reducing spawner delays) are "good" while moving a number down.

I think I'll just leave it as-is.