Hello Reenu,
Thank you for the extra information.
Could you please let me know which is the Product Type, field VDARL-GSART, and Term, field VDARL-SFRIST, you have set in the contract?
According to your customzing, if you set Term (VDARL-SFRIST) to 01 and Product Type (VDARL-GSART) to 30A, you should get the Account Assignment Reference 30A<1.