Default safety lead time

The due date on our works orders is automatically set as the day before the shipment date of the sales order.

I understand this is down to the default safety lead time in manufacturing set up.

I allready tried tying 0D and -1D into the default safety lead time in set up but neither made any difference to the WO due date.

Does anyone know how we can get the due dat on the WO’s to be the same date as the shipment date?

Not always default safety lead time in Mfg setup is taken in consideration if u have routing attached then system will count of time of operations as well, lead time on RM to be procured. See the base calendar as well if u have day off that may be counted as well.