Energy dash: Historic cost 0 when changing from static to entity price

Hi all
Weird thing just happened. I’ve had HA calculating my energy cost (electricity only) for a month now using a static price. This month the price changed and I switched to an entity for the price expecting all historical calculations to remain the same but they all went to 0 cost. Consumtion in kwh is till there and from what I can see the cost is slowly being calculated for today from the time I changed. All my numbers are being recorded to an external mysql and I’m running the latest HA.
Is this expected behavior?

/Fredrik