有control account 時, 點解還要suspense a/c?

Control accounts and suspense account are served for different purposes.

Use sales control account for example.

Sales control account is used as part of the book keeping.U can find the net debtors' balance very quickly by checking the balance of the control account.

For suspense account, it is used to record all errors that can't be located and corrected upon the discovery of the errors. This is a temporary account and when the errors can be located and corrected later, the suspense account would be closed.

btw, I think u should ask the question in a precise way. Becoz yr question is quite strange and I don't know whether what I answer is the one that u want to know.