Cause due to ur level off the deltaP rose further (since the auto cruise mode was not yet reached). Adjusting the FL ALT assures the correct deltaP again.
Why would levelling off increase the delta P?
Or did you mean that there was an increase in delta P due to the increase in altitude (between the time of the crack and the completion of level off)?
Is there are direct relationship between current altitude and pressurisation, or is there a sophisticated pressure schedule? i.e. a schedule based on the takeoff altitude and the previously set cruise altitude (and the controller follows this schedule irrespective of current altitude unless a Delta P is exceeded)?
Hopefully someone has a Component Maintenance Manual for the Controller. There seems to be a lack of data on this system (as well as a lack of data on the event).
Rgds
NSEU