Default Schedule Ship Date based on the Request Date (Arrive On)

Summary

Default Schedule Ship Date based on the Request Date (Arrive On)

Content

Dear all,  we would need to default Schedule Ship Date on the fulfillment lines based on the Requested Date (Request Type = Arrive On) entered on the Order Header. The default SSD needs to be Request Arrival Date by the customer, minus 4 days to account for the shipment lead time.

We have setup the Pretransformation Defaulting Rules (please see attached). SSD are not getting calculated by deducting 4 days from the Request Arrival Date entered at the Order Header during creation of the order. 

Please suggest how to accomplish this