What about the effect where for some pairs of words that don't theoretically have ordering preference (kiki/bouba vs bouba/kiki), (plus/minus vs minus/plus), (on/off vs off/on), (positive/negative vs negative/positive) have some psychological order that most people use and if the other ordering is used, it sound weird? Does this effect have a name?
Even among words that do theoretically have an ordering preference, some people have different habits. I knew someone who habitually said "three or two", rather than "two or three". Leaving aside the effect of prosody mentioned in another comment, I think the rest of it is habit, together with the brain's tendency to group things. If you're used to hearing "plus or minus", your brain may be grouping it together into…
"two or three" means "likely two, maybe three"
Here, the ordering is significant and has nothing to do with a habit.