ZGGBS000 work fine for field G/L account(KOSTL) but not field Order(AUFNR)

I assign value to following field in ZGGBS000. But the final accounting document can only changed the G/L account (KOSTL) but not the field Order (AUFNR). Any one know the reason? How the field AUFNR can be changed?

BSEG-KOSTL

COBL-KOSTL

BSEG-AUFNR

COBL-AUFNR

Best Regards,

Chris.