Stephen,
It is amazing how things get changed. My family name, ROBBINS, is spelled with 2 B's. however some , even today, spell it with 1 B. This made it very confusing to research my father's family in the Civil War.Because of the two spellings, there were duplicate records sometimes for the same person.
I have seen two spellings for McIntosh as well. The other being MacIntosh.This family name is from my father's side of the family as well.
Len