F&O allows you to create a brand new Procurement Category Hierarchy - however, switching to that new hierarchy is nigh on impossible if you have any open POs - because of a setting deep in the procurement policies.

Specifically - the category policy rule can only apply to the active procurement category hierarchy. We suffered from this as POs raised under the new category had no vouchers created (that feature is controlled by policy). There is literally no solution, other than closing down all open PO lines with the original hierarchy and creating new lines, which we have had to do.

This needs an Infolog warning - "Changing Procurement Category Hierarchy will block procurement policy being enabled on POs created on the old hierarchy". To have no warning risks another company going through the an extremely painful recovery exercise.