How To Customize AR SLA to derive accounts based on Customer Class in Oracle Fusion Cloud

Summary:
Hello All,

We have a requirement to derive the AR revenue account (for Invoices and Credit Memo) based on Customer Class (setup at the Account level) of the customer selected in the AR Transaction.

For this we are planning to customize the AR SLA , in which we are planning to create a new custom mapping set , a new custom account rule , a new custom JERS and assign that JERS to custom accounting method.

For the mapping set , we have to choose the Input Source , could you please confirm what Receivable source (for invoices and credit memo) we have to choose for Customer Class ?