[Martin M. Klöckener]

I faced the same challenge today and came up with quite a neat solution. The idea is to use Graphic Essentials, so the precomp can be used in multiple instances and thus the point control is always dynamic.
This solution also takes care of all parenting and transformations.

You basically have to expose the Point Control of your effect (ie Light Sweep) to Graphic Essentials and then have a small expression in the main comp that converts the world space coordinates to layer coordinates.

As it’s a bit complicated to explain, I’ll just attach an AE-document with an example. Hope it helps! ☺

14234_pointcontrolexample.aep.zip