Quantity and food thickness change the way a cooking method works. Reusing the time for a large load can overcook a smaller or thinner portion.
What the observation means
Automatic programmes may also expect a weight or serving input, while a manual timer simply runs for the entered duration. A single portion on a large exposed tray can receive heat differently from tightly arranged food. These are meaningful changes even when the oven's selected temperature remains unchanged.
A useful next step
Use the recipe or packet guidance for the actual portion size and keep the food under appropriate supervision. Note whether the appliance behaves normally with other familiar loads. If it now scorches ordinary portions rapidly across several correctly chosen modes, report that broader pattern rather than assuming every change is explained by quantity.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.