Maybe. You'd have to ask at the individual restaurant but from what I understand from reports here, it can generally be done. More luck is reported trading down credits at a resort food court or CS. If you're in a park and a CS cashier says they can't accept a TS credit, try another CS (or maybe even another cashier) but make sure you ask before you order to avoid surprises.
This is for the basic plan. Deluxe credits are fully interchangeable between CS and TS.