Managing balance in retention
The retention balance is tracked per Subcontracting Procurement Order and Invoice-From
      BP. The balance amount is displayed for the Invoice-from BP and department combination.
      Bookings are processed when:
	 - Changing the retention deducted amount on the AFP
- Counter booking for the deducted retention amount for the old value.
 - Booking for the deducted retention amount.
 
 - Changing the gross retention approved amount on the AFP or the retention release
- Counter booking for the approved retention amount for the old value.
 - Booking for the approved retention amount.