Count Mascetti hosts Perozzi's son as a grammar school kid in the very same house where he lives in Amici miei (1975), but in the former movie we see how the house is first rented by Mascetti when Perozzi's son is a fully grownup adult.
Mascetti already lives in the basement from Amici miei (1975) when Meliselda is two years old. In the former movie Mascetti moved in when Meliselda was an older kid.