@m_adam
Dear Maxime thanks for everything!
But, unfortunally now that I almost finished this part I realized that all this scripting doen't give me the desired procedural result. It just changes the values once but if i change the values of the PARENT object the OBJECT_A (child) is not updated...
Anyway I have to approach it in a different way.

I think I should tag this thread as "SOLVED" and in case I need again help i create a new one.
Please advise me Maxime.

And for one more time THANK YOU both , Maxime and Zipit