There are some nuances to using annotative scaling and a lot of people are overwhelmed by it, at first. I was. It took me a while but it was like all of a sudden, I got it. We don't use it like it was intended, though. We hardly ever have the same annotative object showing at more than one scale. They are set to annotative, but only have one scale assigned to them. It is just an easier way for users, who are less adept at setting up their own stuff, to be able to do so "on the fly". Really, really, basic stuff, but it works and there is no reason not to use it.