Excise Duty showing as 16 % in imported POs

Hi experts,

At present, excise duty is 8 %. We have changed master data thru J1ID. In imported Purchase Order, excise duty is showing correct ( 8 % ) at the time of raising GRN but in purchase order itself, in condition tab, it is still showing / calculating at the rate of 16 % ( which was there long back )

We want to correct if from Purchase Order also. If it can be done thru customization, please guide me the path.

Looking forward for a positive reply soon.

Regards,

( Rajneesh Gulati )