Hi Venkatadri,
I tried myself a couple of minutes before. It is working for me. I entered a sold to party in the "Prospects partner function" and Bill to party relationship was already maintained with Sold to party.
Please check the "Procedure User" assignment of opportunity under Partner determination procedure in Dialog Structure.
Keep the value "1" Minimum occurrence in the partner function "Bill to Party" in Partner determination Procedure.
Please check and let me know the result.
Thanks & regards,
Dinesh.