In OTM, Why doesn’t Unassign Order Movement delete the record in S_SHIP_UNIT table?

Summary:

When we execute Unassign Order Movement Action on Order Movement, corresponding record in S_SHIPMENT_STOP_D table is deleted as desired.

But the corresponding record in the S_SHIP_UNIT table is not deleted.

However, when we execute Unassign Order action on Order Release, the corresponding S_SHIP_UNIT record is deleted as part of the unassignment process. And record in S_SHIPMENT_STOP_D table is deleted.

Does anyone know why the behavior is different here? Shouldn't the record in the S_SHIP_UNIT table be deleted even when we unassign the Order Movement??

Please let me know if anyone could share any insights on this..