I'll leave this here more for myself or others who seek a reference.
I could not find this in the FCOM as well, but this is mentioned in the Service Bulletin on the introduction of the standard 1.9.0 as for 25-Apr-2014 (p. 9):
ELAC L94 to L96:
Basic Aileron up deflection (25˚) at landing for Ground Spoiler efficiency