When you edit the fees for courses of Treatment that involve a payor, there are two additional fields available in the window just below the Fee field:
Adjusting the Fee field automatically blanks the Payor Fee and transfers ALL the fee to the patient.
Adjust the Payor Fee field to have EXACT correctly recalculate the Patient Fee and vice versa.
You can also edit private fees and service items by clicking the 
button, located beneath the Services List. This allows you to permanently change the fees that are presented when charting treatment.