no valuation type extended after GR for material w/ split valuation & batch

Hi all ,

I've activated one material with valuation category 'X' , when it's puchased with account assignment like E and after GR with batch specified , it's posted into special stock (SO stock) , while there is no any valuation type extended automatically for this material.

If we place standard purchase order - account assignment Blank , after GR with batch specified , there is one valuation type extended auto. for it.

what is the reason for this difference ? from my understanding , as long as batch number can be determined during GR process , there must be one valuation type (code same as batch number) extended for the material.

Thanks !

BR/Johny