Final answer:
Returns to bulk are recorded in Section IV - Returns of the DESC Form 1233, which is critical for managing fuel products in military logistics.
Step-by-step explanation:
In the Defense Energy Support Center (DESC) Form 1233, returns to bulk are recorded in Section IV - Returns. This section is specifically designed for the documentation of products that are returned to the supply source after being issued. The DESC Form 1233 is a crucial document used for managing fuel products within the military logistics framework, and it ensures accurate accounting and control of petroleum transactions.