The huge number quoted (like 3-400K) is based on the budget of the academy divided by the number of cadets/mids. Places like USAFA have additional units (10th ABW) that can ramp that number up. They calculate the payback as the value of the education received rather than the average cost per cadet/mid of the installation. Should military training (such as airmanship, BCT, etc.) be allowed to be included in that sum charged to a separated cadet (or LT who is booted shortly after going on duty)? We don't send a bill for military training anywhere else (enlisted, pilots, etc.), so why would we do it just for them? That's why the bill is so much less (~$30K a year equivalent usually) since it is for education and not military training.
That makes sense, thanks for the clarification.