Getting a review to the FCOMs, maximum service ceiling is FL390 with a cabin altitude of 8000ft that gives a differential pressure of 8.06PSI.
This differential pressure is mantained by the single outflow valve on the right rear fuselage, controlled by one of the 2 Cabin Pressure Controllers that receive data from ADIRS concerning pressure altitude and FMGS with landing elev. and QNH during takeoff /landing operations.
I would then say that, in automatic mode, pressurization is indipendent from CRZ ALT or FLT ALT inserted during preflight.
Pressurization profile include standard pre-presurization during takeoff to prevent pressure surge at rotation; climb presssurization with pre programmed law that takes into account A/c rate of climb; descent profile mantaining differential pressure of landing elev. +0.1PSI shortly before landing.... and so on.
Hope to be right and helpful!
Seeya!
