I agree with Checkboard,
I have different PDFs and PPTs about Ice Crystal Icing. In fact, the previous company I worked had an incident of dual engine flame out near Shanghai around 5 years back. The searches about Ice Crystal Icing is around 10 years and mostly theoretical; they believe but not prooved, how it happens. However the EAI using procedure during descent was the same as now, when I started to my Airline life 20yrs ago with B 737.
From B 737 (same as A 330)
Engine anti–ice must be ON during all flight operations when icing
conditions exist or are anticipated, except during climb and cruise when
the temperature is below –40°C SAT. Engine anti–ice must be ON prior to,
and during, descent in all icing conditions, including temperatures below
–40°C SAT.
Regards