Add offset value to Energy Helper

Happy Easter everyone :slight_smile:

Can I ask you something?
Created this energy helper to track the kwh of my heatpump. The source of this helper is a shelly plug.
So far so good !
Q: how to add some value to the helper as a start value? I created the helper two weeks after the installation of the heatpump and I would like to add the first two weeks of consumption to the statistics as well.
Any simple way of doing this ?
Did take a look at the ‘states’ in developer tools but doesn’t work; those values are reset after 10 seconds or so?! or maybe I’m doing it wrong ?

thanks in advance