If P4210 has a future commit, quantity goes to quantity shipped instead of backorder?

We use JDE 9.2.7.2

When using P4210, if the order is outside the commitment window it goes as future commit. Why does the SO put this quantity as quantity shippable instead or backorder when we have no inventory? This is really confusing. I know it does not take future commit into account in summary of availability, but this makes the SO get a shipment number when it's not available. Very confusing.