I sent the following problem report to support.gr@tp-link.com but the reponse I got was that RSSI is not a meaningful measure of transmitted power and the difference in my RSSI measurements was due to changing channel:

I am using a TL-WA850RE v6.0 with firmware version "1.0.0 Build 20181108 Rel. 56911".

The issue I'm facing is that it keeps reverting to the highest transmit power even though I have selected the minimum coverage area.

Steps that seem to reproduce the above issue:

1) Have the device in "Range Extender" mode and connected to the host network.
2) Select "Min" for "Wi-Fi Coverage".
3) Check the signal strength transmitted by the extender from a device within range (RSSI value).
4) Change the channel of the host network and wait for the extender to reconnect. Alternatively, run the "Wireless Scanner" without selecting a new network to connect to.
5) Check the signal strength (RSSI) again.

The measurements in my case are:

Step 3: -65 dBm

Step 5: -59 dBm

The above indicates that the extender is using its maximum transmit power while the minimum coverage option is still selected.

I then highlighted that clicking on "Wireless Scanner" without selecting a new host network also produces a 6 dB increase in received signal strength:

I am confident this is a bug in the firmware. The RSSI values I'm reading from a stationary client (in an environment with little interference) very strongly indicate the extender is transmitting at full power and not respecting the minimum coverage setting selected.

Clicking on "Wireless Scanner" without selecting a new host network immediately shows a 6 dB increase in received signal strength. The RSSI readings from 2 stationary clients remain high until I set the coverage setting of the extender to "Mid" or "Max" and then back to "Low". After doing that, the signal strength drops by 6 dB. (I have tested this multiple times and it's extremely consistent.)

Please try to reproduce the issue described above (no need to change channels, just click on "Wireless Scanner") and see if it can be fixed with a firmware upgrade.

To the above, I got this short response basically telling me to bugger off:

As i stated before the RSSI values can not be associated with the transmitted power so you can not expect the change in one to affect in the same way the other.

So now I'm posting here, and my main question is whether the above is representative of TP-Link's stance against user-reported issues.

Does TP-Link consider users to be idiots? Because that's my interpretation of the last response I got (highlighted in red above).

In my experience, a 6 dB change in RSSI is highly indicative of transmit power if the readings are consistent and reproducible.

In the end, it's a minor issue and I'm not expecting a quick fix. Still, it would have been nice if someone actually tested it and then handled it internally if the issue was reproducible for them as well.