Thanks Hector for your reply.
I think my explanations were really bad because I haven’t absolutely no problem dealing with pre-compositions. I have a senior level with After Effects so it’s not the problem.
I’m looking for an expression to manage time as I have to temple a project for clients that can be quickly and easily modified..
I’ve already seen expressions used with precomp and time-remapping but not exactly in this way, so this is what I’m looking for.