Propagate submission date to child tables

Hi to all,

in order to store collected data in our PostGIS database, I am looking for an efficient way to get data from Central.

I developed a set of PostgreSQL functions that work really well as they automatically create database table from per table ODATA query. They also add new attributes to those tables if question are added in forms.

All works really fine but I would like to improve it a little bit. In order to get fresh data in our tools as soon as colleagues are back to office, I query Central twice an hour.
As I said everything works well but each time I download all submissions since the form has been created. It is not so much but it weights approx 1 Go each day (from 8am to 8 pm).

I tried to use the $expand=* option combined to submission date filter. It gives back a light json with recent data but the json is really much hard to automatically transform to database tables.
I was wondering if it would be possible to propagate submission date to child tables so we could use such a filter on those tables.