Just so everybody is on the same page (not a Airbus code0)
The -800, -900 Packs will output the lowest zone temperature selected, whether it is the flight deck, fwd or aft cabin. That air then goes to the mix manifold (the flight deck tees off the L/H Pack output just before the manifold). After the air exits the manifold for whichever zone its going to, hot air is added through the trim air valves to raise the temperature to that selected for the two zones that need it. If the trim air is turned off, the L/H Pack supplies the selected temp. for the flight deck and the R/H Pack supplies the average temp. selected for the fwd and aft cabin.
Of course if its a -600? or -700, there are only two zones. No temp. or trim air valves, only a Air-Mix valve in each pack to control the Pack output temp.. L/H Pack for the flight deck, R/H Pack for the cabin.