When control accounts are maintained, the individual ledgers of customers become memorandum accounting books.
Where control accounts are not maintained the individual accounts of suppliers will obviously form part of double entry system.
However use of control account would be beneficial as they can be prepared quickly to provide the total outstanding balance in customers’ and suppliers’ accounts without having to add up all the individual accounts.
As a result, the control account is often used as the account for double entry, and the individual ledger accounts are maintained as memorandum accounts.
In the examples cited by you may assume that control accounts are not maintained and therefore individual accounts are used to record entry.
Hope this helps you. If you still have doubts let me know.
Andrew
