Best answer by Mw2870
This is what I understand:
Your smart meters will take a meter reading of usage every 30 mins, and then once a day will upload that data to OVO. The smart system then learns the "energy signatures" of the devices in your home and attributes them to the available options on your energy breakdown in My OVO. There is some room for error in this calculation as the only data it has to work on is your electricity usage every 30 mins.
More info on it here https://www.ovoenergy.com/help/energy-breakdown
Is your energy breakdown profile up to date?