The Dev notes on the Wiki page say this..
The number of groups used by the AI Commander to conduct a recce/attack, reserve or defend operation is determined by the AI Commander's strategy.
Invasion: 4 Attack, 1 Reserve, 2 Defend
Occupation: 4 Attack, 1 Reserve, 5 Defend
If I have my AI Commander set to Occupation, and I have the "Readiness" option set to 50% does this mean that only 2 of the 4 attacking groups will now be on attack?