I read from manual:

If this value is set to be larger than the maximum transmit power that is allowed by the local regulation, the regulated maximum transmit power will be applied in the actual situation. Note: In most cases, it is unnecessary to use the maximum transmit power. Specifying a larger transmit power than needed may cause interference to the neighborhood. Also it consumes more power and reduces longevity of the device.

My EAP 225v3 shows:

Few questions (I'm doing a 3 AP deployment, on 1-6-11 channel at 20MHz respectively, one per floor, big walls):

1. does this mean I can set a value from 10 to 20?
2. what is more powerful? 10 or 20?
3. what should I put? Of course more power means better reception, but I also suspect more interference and RF pollution.

Thanks a lot