Increasing your Efficiency ability increases the amount of damage converted to the current AEGIS damage type, and increases the amount of AEGIS shield restored when using a direct heal ability. Note that AEGIS healing only restores the strength of shields which match your currently active weapon controller type. Each level also increases your Skill Point cap by 5.
The amount increases with each skill level. Note that the numbers below are total increase for that level, and not cumulative with the previous levels: