Option to set up a custom starting range for the battery report

Hi, I would love to set up a custom starting range for the battery report.
I'm using my model 3 for six minth now and of course it is affected by a small battery degradation.
I have now completed a 90% charge and Teslafi (which I'm using a few days now) is now reporting 493,78 km instead of the original 499 km as my "starting range". I would like to correct it togehter with a custom date (e.g. buying date of the car, etc.).