We all obviously operate the same, I was taught to read "anticipated" two ways:
1) it is not neccessary to wait until you are in cloud, it is a good habit (read: procedure) to turn EAI on before entering cloud; same logic for climbs in cloud with TAT say +12 deg C;
2) Aniticipate is a good thing, i.e. for TKOF at OAT 4 deg C and cloud base below planned thrust reduction ALT, set EAI on and calculate performance data accordingly, or I personally would not be ashamed to turn EAI for VMC approach to snow covered airfield with precipitation or cloud in the G/A sector (again, low TAT);