WING7, I do not know about the specific Airbus position, but in common with some modern aircraft, experience may indicate that continuous ‘anti icing’ during cruise may not be justified.
Much of this depends on how the aircraft system has been certificated. Anti icing is normally associated with continuous use, more likely at low altitudes, whereas in-flight intermittent ‘de-icing’ could be used as required, either where ice accumulation has been identified, or if there is temporary risk of encountering higher categories of icing during the cruise; in which case the system's use becomes anti-icing; crew awareness / decision.
Ask the manufacturer to comment on the certification standard and recommended practices for the system.
I recall that there has been a significant rethinking (amendment) of the icing certification standards. This may change definitions and system use.
Also, even if the new regulations are not retrospective, Airbus may have adopted the best best-practices in operation or has related previous certification to the higher standard; indicating that an older aircraft would meet a new standard, even if formal documentation does not state that.