On AZ Timetable (also on line) You can see alla A32s seat configuratin with a business 3+2. I think becouse these aircrafts have been used mainly for international flight or national with business services (now only MXP FCO).
Now, with the retirement of MD80, these aircrafts are strongly used also in internal route: f.i. two daily GOA FCO are operated by 320. In one of this flight I see a all economy 3+3 configuration. Whoat about? AZ use different internal configuration on internal international flight (as they are doing with MD80)?