No. Volume does not describe the usable shelf width, depth, height or support arrangement. A tin can exceed one dimension despite a generous quoted capacity.
What the observation means
Lids, handles and the space needed for safe removal also matter. Different cavities on the same cooker can have very different proportions.
A useful next step
Check the manufacturer's accessory dimensions or measure accessible cold spaces only where safe, without dismantling. Use compatible cookware that leaves the required clearances. Do not rely on the litre figure to justify a tray touching a wall or preventing the door from closing normally.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.