How does safety stock days of cover method works?Required plan output explanation

Summary:

i ran a supply plan in oracle fusion using days of cover method for my component item.

Scenario:

The component item had on-hand inventory of 100kg.The Assembly item independant demand was 2000MT with 100MT fixed safety stock quantity.

Now will the dependant demand for component item will be calculated using 2000 or 2100 MT of assembly item?

IF 2100 then considering component usage the dependant demand is=2100*18=37,800Kg.

My days of cover were 90 and demand period days were 180.

Plan output:

Questons:

1.In my input data days of cover were 90 so Why in plan output only 75 days are being considered?

2.For 10/23/25 why there are no planned orders and how safety stock is being calculated?