When an area cloaker has the area cloak option enabled, the unit spends self-cloaking energy when cloaked, whether it is under its own area cloak or cloaked by another area cloaker. This energy usage happens even when the unit is powered off, as long as the area cloak option is enabled (even though its own area cloaker is not active when powered off) and the unit is cloaked. When the area cloak option is disabled, the self-cloaking energy is not spent, although the unit is still cloaked if it is under an area cloaker.
Using Cornea as example:
Self-cloak cost=1 E/s
Radar jam cost=1.5 E/s
Area cloak cost=12 E/s
Energy usage when area cloaker is active is 14.5=1+1.5+12. The self-cloak cost of 1 is redundant when its area cloak is active, so it should actually only cost a total of 13.5 E/s to do area cloaking.
Cornea and commander with personal cloak+area cloak modules are affected. Iris is not affected because it has no self-cloak. Commander with one but not both of (personal cloak, area cloak) is also not affected.
. Note the area cloak states and energy usage.