Where to change date_add to date_upd for new products module?

[MuniGod]

I don't find where to change 'date_add' to 'date_upd' to show on ps_newproducts module hook.

I changed in Product class, NewProducts controller.

In link/new-products everything OK and showing last products by update time, but at home, where hooked ps_newproducts showing last 8, but by adding time.