I'm glad you're still active on this behavior: it's easily the most used in my collection.
I don't know if it's easy to do, but is it possible to add an action to change the parameters of the starting point?
For example, A tween object that, when spawned at a spawner object, has a target at the bottom center of the screen. If the spawner moves, the tweening object doesn't change it's course. I would like to be able to have the tweening object update it's coordinates to the spawners new position as if it's on a tether. I think this would be work if I could update the tweening object's starting point. Is this possible?