I didn't interpret their comment that way. It's common to have a handful of managers under you, but reference to their reports as your managees as well. That easily reaches 100-200 people.
I think it's the "large teams" bit that makes the OP appear to be saying the "team" is up to 300 people. Team suggests a group of equally ranked members to me.
You can't really have a team of 300, sounds more like a management speak version of team.
Of course only the poster knows for sure their intended meaning.