Service Parts Planning(SPP) - Inventory optimization (IO) safety stock computation logic

We have a part where the forecast is rolling to Master PDC and Safety Stock is being generated at Master PDC.

Master PDC=IC

Local Sourcing rules:

1. IC-> BUY FROM SUPPLIER

2.. GA -> TRANSFER FROM IC

3. PA->TRANSFER FROM IC

4. TX -> TRANSFER FROM IC

5. CH -> TRANSFER FROM IC

Global Sourcing Rule

1. IC ->TRANSFER FROM IC

2. GA -> TRANSFER FROM IC

3. PA->TRANSFER FROM IC

4. TX -> TRANSFER FROM IC

5. CH -> TRANSFER FROM IC

Request you if anyone has information on the below queries :

1.

HOw is IO Safety STock getting calculated in case where forecast is getting rolled to Master PDC.??