"100% Self powered" but still receiving charges for energy import

[charlesj]

Here is comparison of my Tesla and Enphase readings for yesterday:
55.6KWh PV production reported by Tesla and 53.6 by Enphase. 43.9 house consumption in Tesla and 35.7 in Enphase. I have whole house backup option installation so Enphase and Tesla readings should match for consumption.

BTW my grid voltage is somewhat on the hot side. It is rather common that I have 247V-249V coming from the grid. Unfortunately my utility company has 5% acceptable policy for over voltage so anything below 253 is considered to be acceptable. It is possible that Enphase assumes 240V in calculations but I somewhat doubt it.

OK, here is my solar production for yesterday from Enphase and Tesla, 100Wh difference, about 0.5%. Now, house usage calculation differences must be what and how it is calculated, battery recharging, etc.