Question NavMeshAgent confusion....

This is rather confusing to me...

You can create different agents, but they don't seem to apply to the component, or do you override them?

And what about the Bake tab, if you have multiple agents, why can you only bake one type?

And what if you scale the parent of the navmeshagent, the gizmo changes accordingly, but the change has no effect on the radius of the navmeshagent...

edit: Is the NavMeshAgent Component Obstacle Avoidance Radius broken ?

Can someone please explain?
Thanks.