Client upgrading to A9.3 has phantom items at the top level

One of my current clients is upgrading from A7.3 to A9.3 and have all of their top level / sellable items set up as phantoms.  They are generating a forecast for these items and are looking for the phantom level forecast demand to flow through these items in the JDE planning program P3482 to generate MPS messages at the next level down from the phantoms.  I know that the phantoms should be defined as manufactured items, but they have designed other parts of their system around the sellable items being a phantom item.

My question is does anyone know how to make the planning programs work properly with the forecast demand at the phantom item level?