When you set the target power, that is the power setting the AP is going to attempt to use.  As I understand it, what would be limiting it to reach that power is the capability of the AP itself or regulatory domain restrictions.  Taking a look at the AP data sheet (last page), there are multiple data rates that the AP is limited to using 15 dBm as a maximum. It's possible your just hitting the maximum capabilities of the AP on the selected channel.  I HAVE noticed (in the past at least) that the dashboard will let me set a higher target power than an AP can support.    If the client is connecting to another AP, maybe consider lowering the power of the other AP's instead? That may be what's causing your trouble device to jump to an AP in another room. ... View more

This thread raises an issue that I have filed numerous cases on over time.  While I like how the Dashboard simplifies things and tells me I have a MR 27.5.1 network, for example, please please please have the Dashboard identify the MR devices that top out at 26.8.1, for example.  What a pain this is to re-discover this issue time and time again.   And, while we're on the topic, the MT devices apparently use the same firmware as the MR devices, and the latest two 27.x firmware releases are MT-only and cannot be applied to a MR-only network.  Please please please create a separate MT FW and keep the MR clean.  It's already buggered up enough already (see paragraph above).   Thank you. ... View more