NotifyChange is for when something outside of your AceConfig changes a value while the config is open and you want it updated. Changing a setting within AceConfig automatically updates your options. Your issue is that you set a hard value for your description when you should have used a function if you want it to be dynamic:
Code:
useClassRep = {
order = 40,
name = L["Override some default racial reps with class reps."],
desc = function() return (L["Your class reputation is %s"]):format(racialRepName) end,
descStyle = "inline",
type = "toggle",
width = "double",
get = function() return db.useClassRep end,
set = function(info, value)
db.useClassRep = value
racialRepID, racialRepName = self:GetRacialRep()
end
},