This field applies to APS.
With the Time Fence feature, you can specify a quantity of inventory and planned supply that is reserved for demands due within a defined period of time. The system does not allow any demands due later than this time fence to deplete available inventory or supplies below the "preservation level." This level is equal to the item's Safety Stock value multiplied by the Preservation Level Multiplier field.
For example, suppose the demand's due date is later than the item's defined Time Fence, and the demand quantity is 100. On-hand inventory and planned supplies total 100, and the safety stock is 50. Preservation Level Multiplier is set to 0.5. The quantity the system preserves is half the safety stock (0.5 * 50 = 25). So, the demand can only allocate 75 of the available inventory and supplies.
If either the Safety Stock or Preservation Level Multiplier value is zero, the entire quantity of inventory and supplies is preserved inside the time fence.