Method Of Computation "F" in E1 9.1

The client uses method of computation "F" and occasionally forces the projected final to be less than the Revised Budget amount and less than the Actual Amount plus Committed Costs.  The client does not believe the system should allow the forced amount to be less than either Revised Budget or Actual Amount plus Committed Costs.  However, per my understanding, if you "force" the projection and it is below RBLA or AA+PA, then the forced amount becomes the projected final amount.

What is the correct computation?  Should the system allow the forced amount to become the projected final amount when it is less than RBLA or AA+PA?   Thanks.