Mongo
The incident quoted by you is not appropriate for the topic because it is related to a mismatch of gain control when slats and flaps are in the wrong combination in normal law. This is not a problem when flaps are three or less and in correct combination. However the sentence given below in ECAM procedure F/CTL FLAPS FAULT/LOCKED is the reason:
FOR LDG (IF FLAPS ≤ 3)............................ USE FLAP 3
Do not select CONF FULL, so as not to degrade handling qualities.
If it degrades handling qualities in normal law then it is more so in direct law.