Hello Siddappa,
From what i could figure from your query is that you have already transferred the Payment Terms created in the ECC system and it is currently available in SRM system. This is also visible in the mentioned tables.
However when you create the PO then it is not shown in the payment terms field. Can you please provide with the screenshot on where exactly you are checking the payment terms in the PO.
The payment terms specified in the vendor master gets picked up during the creation of the PO.
Let me know more about this issue to help you better. If the payment terms is replicated and available in the table then it should be available for selection as well.
Regards
Pramod