Thanks for the notes! I updated the description with a warning. Currently, the layer comments is the best way I know to store information.
Let me try to explain better what this automation is meant for:
It’s kind of a mix between the two ways of precomposing.
If you leave all attributes, you keep all the changes you made to the layer outside of the precomp, but the problem is that the precomp contains inside the whole length of the original footage. If you then try to manually shorten it and keep only the required part, it messes up the position of the keyframes and the the In/Out points.
If you move all attributes, you get a precomp that is the correct length, but all the changes you made to the layer are now inside the precomp.
This automation leaves all the attributes outside of the precomp, but keeps only the part of the footage that is actually used inside the precomp.
You can’t precompose multiple layers together while keeping the layer attributes outside of the precomp, that is why it precomposes each layer individually.