We want to prevent the re-scheduling of a sales order which has a past due date when the quantity/wa

The reason why we would not like the system to update the past due SSD when warehouse or quantity is changed is due to fact that we are measuring On Time Delivery performance based on SSD and would like to take corrective action whenever there is a delay in shipping a order line. But the current situation is that change results in SSD updating to current date due to which the line is always considered as on time delivery. Hence we are unable to trace and perform corrective action.

Ex: Order line with SSD as 10-JUN (past due) shows up in our past due reports informing leadership that it was not delivered on time by warehouse. But when warehouse is changed on order line on 17-Jun (may be the item is available at another warehouse) , SSD gets updated to 17-Jun (current date / sysdate) and when it's shipped on 17-Jun, the report no longer shows that there was a delay in shipment. It would always treat it as on time shipment even though we missed the original ship date.