Final answer:
All options listed are important controls for the issuance of credit memos, thus there is no 'exception' among them. Credit memos must be managed carefully with proper segregation of duties and required documentation for returns and errors.
Step-by-step explanation:
The question asks about the control measures for issuing credit memos and identifying which one is not important. It's important to understand that credit memos are documents issued by a seller to a buyer, reducing the amount owed by the buyer because of returned goods, errors, or allowances. They are an important aspect of revenue and accounts receivable management.
The following points depict adequate control measures except for one:
All the options listed above are indeed important controls, but since the question is asking which of them is 'except' (not important), none of these controls can be considered an exception, as each one plays a significant role in managing the issuance of credit memos effectively.