Does it matter if the dish is cooked on a tray, on a baking and roasting rack or in an oven dish when using Smart Food ID (SFID)?

No; as long as the food is clearly visible, it doesn’t matter.

If the food is completely or partially covered (e.g. by aluminium foil or a lid), it cannot be identified.

If you use non-standard and very heavy cookware (e.g. pizza in a Miele Gourmet oven dish), the result might not be what you expect.