Can we import data from SF Account and Account relationshipship fields together into a CPQ quote?

Summary:

We have an integration file importing data from an Account's Account Relationship object into our CPQ quote. If a field is missing information, we would like to pull it from the Account object.

Content (please ensure you mask any confidential information):

The field we are looking at is a Sales Credit Number. This is often missing in the Account Relationship object. Then we would like to pull it from the Sales Credit Number on the Account. In our integration file, the from statement is from "Account_Relationship". In the SOAP file we have included in the query string "Account__r.Id, Account__r.Primary_Sales_Credit_Number__c". But this caused the following error: