Item Description Edited in the Sales Order is not updating on Purchase Order once approved

There is a field in the Item Record, under the Purchasing Inventory tab, that can be enable to have the Description be copied from the Sales Order: Copy From Sales Order. 

This field, however, is intended only for Special Order/Drop Ship Items where the Purchase Order is created directly from the Sales Order. 

By this system's design, it explains why a standalone Purchase Order cannot seem to copy the updated Description from a Sales Order because there are no Created From links between the two transactions.