Can Stock Item additional fields be displayed on a subcontract PO?
The software allows User-Defined (or "Additional") Fields to be created against Stock Items. These custom fields allow a place to provide further information/specifications against Stock Items. These fields can be added to the PO so that whenever you purchase the item, the form can automatically grab the additional information/specifications for the stock item being purchased and place it on the form.
That said, this is not possible for subcontract PO's. The reason it isn't possible for a subcontract PO is that with subcontract PO's you are not actually buying the item. What is being purchased is a service so, therefore, the stock item ID itself is not actually listed in the Reference ID on the PO detail line. Instead, a subcontract ID (which references "Service - item ID") is listed. Since the purchase is for a service, and not for the item, the PO form cannot pull in data from the Stock Items module. If additional information/specifications need to be listed on a subcontract PO then you would need to manually input this information into either the Job Subcontracting screen (when preparing to create the PO) or directly into (Purch > Purchase Orders > Details tab > Notes subtab) after the PO has been created.