I turned down the transmit setting half way on the router and clicked apply. When it was done, the transmit power doesn't look like it decreased and the setting disappeared.
I'm wondering what happened.
An original RT-AC66U? What firmware are you running on it? What is the goal of turning the radio's power level down? What band are you doing this to? Did you reboot the router afterward?
I'm running the latest firmware. I was swamping the neighbors. 2.4 I looked at my wifi after I clicked apply and then logged out. I just went back in . The setting is back and I rebooted it. I think it did go down a little.