Does anyone know what the "mod" column does in the "Interfaction Relations" list box of the Faction Form?

I was hoping is would allow you to apply a weight ... So PlayerFaction hates Thalmor Faction more than Mudcrab Faction.

But I'm not sure how to test if that is what it does (and, from my testing, I don't think that is what is does, anyway!)

Anyone used it??

ta for any help