this is just quick note. One reply got me thinking to put every code I wrote here as an example on the apex.oracle.com website so you can try it yourself. Here is the new link: https://apex.oracle.com/pls/apex/f?p=70928:1. I’ll update the application with the other articles, but for now I put there only the one with interactive grid calculations and validations.
Hope this will be beneficial for you.