The point of the postprandial test is to check the effect of that meal so that you can avoid it or modify it in future if necessary.
It is generally accepted that non diabetics would get back to close to their preprandial reading after 2 hours and type2 diabetics on a low carb diet aim to achieve a rise of less than 2 mmol/L.
The spike after starting eating could be at any time between 30 mins and 90 mins so could easily be missed unless you are using a CGM, also what that level should be is less well defined.