Could we add another BOM line type of Stockable Phantom? Phantom would remain as "always explode" at Estimation, regardless of any Physical on hand or Physical available of the Phantom item. Setting a BOM line as "Stock-able Phantom" would cause MPS to first check for available inventory if this is not zero (or less) create BOM line with a per series of the full exploded lot size for the lesser of Quantity required and Available physical. If this leaves any remaining Quantity remaining then treat this the same way as a regular phantom with the exception of promoting the per series to the full exploded quantity. Switching the per series is needed to cope with partial coverage by available inventory.

This solves the problem of ignoring on-hand phantom if YOU HAPPEN TO HAVE SOME. But more importantly, this can be used to fully fill the gap that D365 does not have Use-up effectivity, where you want to use the old component until its inventory is depleted. I understand that this idea can only be applied to Optimized planning. Firming the planned order would need the same treatment, including a line for the phantom and its physical available quantity only adding the phantom's exploded lines for a remaining quantity if a remaining quantity exists.