Your'e right, I was just being a little simplistic in my explanation. To be more specific, the L/H pack will output the temperature to attain the desired temp. in the flight deck. The air that doesn't go to the flight deck from the L/H Pack ends up in the mix manifold with the R/H pack output and then to the cabin. The R/H Pack outputs the temp. needed to attain the desired cabin temp., compensating for whatever the the L/H pack temp. output is.