Theres an easy way to edit or offset the temperature in Domoticz:
1) Click on Devices (Outlined in Red)
2) Click on the green arrow next to temp + Humidity, then name it and save it.
3) Now it should appear under your home page devices
4) Click on Temperature tab now
5) A new node should populate that you can edit, Click on Edit
6) Set the new adjustments, can be any value amount that you are seeing an offset of (such as offset by -5, or offset by +10)
7) Click update.
You will now be able to view all temperature changes throughout your Domoticz software for the temperature sensor of the Multisensor 6.