Question about safety stock method BS

Hi guys,

I am new to the APO .  Could someone help me on this issue?

1.

I am testing safety stock method AS/BS .

AS works fine. But BS does not work.  Safety stock is reflected in the planning book.

I use the same way as i i did for AS.  Set safety stock method_BS in product master and then go to Safety stock planning, click execute. Planning area is 9ASNP05.

It just does not work.

2. Second question is :

if I set the target days' supply to 5 days. And use safety stock method SZ to set safety days' supply to 5 days. Why most of the time target stock level is great than safety stock.

My understanding is I set them all to "5 days"  which means target stock level should cover next 5 days'' demand and safety stock should also cover 5 days' demand.  So they should be  the same.

Could someone give me any advice?

Thanks a lot