Register lag when accessing Stiebel Eltron Heat Pump via HA Modbus Integration

Configuration
1

Started to play around with the HA Modbus integration to read data from my Stiebel Eltron Heat Pump. The example is as easy as it can be:

modbus:
  - name: stiebel_eltron_hub
    type: tcp
    host: 192.168.x.x
    port: 502
    sensors:
      - name: se_aussentemperatur
        unit_of_measurement: °C
        slave: 1
        scale: 0.1
        input_type: input
        address: 506
      - name: se_wwisttemperatur
        unit_of_measurement: °C
        slave: 1
        scale: 0.1
        input_type: input
        address: 521

Everything work as expected but what I’m observing consistently is a register lag by 1. I.e. If I want to read Modbus register 507 I have to use address: 506. This is confirmed by e.g. qModMaster where I get the value of register 507 when requesting 507.

Is there any parameter in the Modbus Integration I missed out which might cause the register lag?

Thanks for your comments and ideas!
Tiro

2

MODBUS starts counting at 0 while documentation starts with 1.
Not aware that you can change this in the configuration