That's my feeling as well, but unfortunately, that's not how it works. I have a couple in my tree for which I have a direct line of decent from all 4 of their children. 2 of the children are 8th great grandmothers and 8th great grand aunts. The grandmother relationship is shown. The other two are 9th great grandparents. For the 9th great grandparents, it's the 8th great grand aunt/uncle relationship that is shown, and instead of little yellow arrows showing a direct line relationship, they have the dark grey arrow instead (in the people workspace, family view. See attached screen shot if that was confusing :-)