If you have an Addition that is a percentage type, it is possible to calculate a percentage of another Addition.
Tick Process Loading in the Addition that is calculating the percentage e.g., Casual Loading or Shift Loading. This field is only available on a percentage type Addition. When the addition is calculated, it will include any other Additions where Include in Loading has been ticked.
Tick Include in Loading in the Additions you want to include in the calculation of an Addition where Process Loading has been selected.