An incorrect time on the meter won't affect the readings or averages. You can re-adjust it according to the instructions in the manual. Occasionally I have noticed mine are wrong and have simply re-adjusted them. Sometimes it can be an early warning the batteries are dying.
I never take much notice of mine and never use the meter averages for anything at all. I record all my readings on an excel sheet in columns with the date down the side and appropriate headings with a note column at the end. That way I can average individual events, such as fasting, before lunch, 1 hour, 2 hour, before tea, random, bedtime, whatever I want. If I were to use my meter averages it would be nonsense in my case because of duplicate testing if I see an unexpected number. And we do see unexpected numbers, especially with the Codefree!