This idea grew out of discussion up on the general board across two threads and about six months. As it stands, AToW doesn't have any professional military education past OCS. So here's one idea to remedy that:
Command and Staff College (500 XP + Field Costs)
Prerequisites: Officer Candidate School, Rank O-4 or higher
Automatic: [Attributes] CHA (+100 XP), EDG (-100 XP); [Traits] Combat Sense (+100 XP), Connections (+100 XP), Fit (+50 XP), In For Life (-100 XP), Patient (+50 XP), Reputation (+100 XP); [Skills] Administration (+25 XP), Leadership (+25 XP), Protocol/Affiliation (+25 XP), [Flexible XP] (+125 XP)
Fields
Basic (+1 Year): Staff Officer
Note: Command and Staff College falls under the same Stage 3 exception as Officer Candidate School regarding repeating schools of the same type (AToW, page 71 refers).
Staff Officer Field
Requirements: Rank O-4 or higher
Administration
Interest/Military History
Leadership
Protocol/Affiliation
Strategy