Final answer:
The statement that the commission system offers flexibility and may include additional services at no extra charge for large clients is true, given the agencies' discretion in providing more comprehensive service packages.
Step-by-step explanation:
Proponents of the commission system argue that it provides flexibility due to the potential for agencies to perform additional services for large clients at no extra charge. This assertion is supported by the fact that agencies often have the discretion to offer more services as a gesture of good customer relations or as part of a more comprehensive package for significant clients. As a result, while the commission system may appear rigid, it often incorporates other services to accommodate the needs of large clients, aligning both parties' interests.
Therefore, the statement that the commission system is more flexible than it appears because agencies often perform other services for large clients at no extra charge would be considered true. The statement is true. Proponents of the commission system argue that the system is more flexible than it appears, as agencies often perform other services for large clients at no extra charge. This means that agencies are able to accommodate additional requests or needs of their clients without requiring additional payment.