Pulse meter accuracy not correct

First of all - i have scanned all the forum threads about this, and some problems got solved, but not this one…

I have an ESP8266 connected to my Power Meters S0 relay switch.
(PDF on my meter can be found here : https://search.abb.com/library/Download.aspx?DocumentID=2CMC485003M0201&LanguageCode=en&DocumentPartId=&Action=Launch )

Settings in the meter;
Pulse Frequency = 1000 imp/kWh
Pulse Lenght = 100 ms

My ESP is wired up like this; (with pulldown resistor)

S0 ------------ VCC
S0 --+-- 10k -- GND
.    |
.    +--------- GPIO12

ESP Config:

  - platform: pulse_meter
    pin: GPIO12
    accuracy_decimals: 2
    unit_of_measurement: 'W'
    name: 'Elmätare Puls'     
    internal_filter: 100ms
    timeout: 2 min
      - median: 
          window_size: 3
          send_every: 1
          send_first_at: 1 

      - multiply: 60 # (60s/1000 pulses per kWh) 

      unit_of_measurement: 'kWh'
      name: 'Total kWh Elmätare'
      accuracy_decimals: 2
        - multiply: 0.001  # (1/1000 pulses per kWh)

Before i added the “median” filter, i had spikes every minute or so… But after i added that, the spikes where gone. As seen in the pic below.

Now to my problem!
I created an Utility meter in Home Assistant, so i could calibrate that to show the same value as my Power Meter, to “feed” the utility meter, i used the “total kWh” from Pulse_meter.

Now, after 24h of running, my Power Meter says “29792.69” but my Utility meter in Home Assistant says “29792.55” so there is only .14 difference, with is not much! But if that´s the difference in 24h, i assume it will be alot more after a month. And, it feels like something is not right, since it’s not the exact value…

Does anyone have some ideas what could be wrong here, or what i could try to change?
I will be using this meter for reading the Power Meter to charge for electricity used, so i really need it to be as accurate as possible…

I will gladly “buy me a coffe” to the person/s who help me solve this!