[werk_ag]

You don't know (nor I) if for their purposes, they are sending the Ambient Pressure instead of the Equivalent Sea Level Pressure. Maybe its better not be so critical...

By the way, what your sensors are sending for sensor.community is also Ambient Pressure, but what is show on their maps is the Equivalent Sea Level Pressure. Their servers do the calculation, they have the data needed for it!

   

So, the "correct measurement" is also a question of what the purposes! We don't know the purposes of the "chillibits"

We are going a bit off topic.