Ship-to Account Number" LOV should be same as "Bill- to Account Number in Project Contract

Summary:

when we are creating new contract (Project Contract) for Customer billing that time we have selected "Primary Party" as customer name.

Issue is that when we are going to "Parties" area Selecting "Bill-to Account Number" so Bill to Account Auto default showing when select Bill to account "As customer Name and Customer No" After that all "Bill to site "showing as "LOV" as per customer.

But when we are going to "Ship-to Account Number" so that should be auto Default as "Bill-to Account Number but Current Scenario is , There are no

LOV showing Respect of Customer.

But I want to "Ship-to Account Number" LOV should be same as "Bill- to Account Number"