Why would you not want to adjust the watts

Question

Some vendors have adjustable power levels on their access points and some don't... Why won't some provide that feature?

Answer 1

The FCC in the US states a maximum output power for devices that transmit wirelessly.  In other countries, different regulating bodies may state different limits.  Officially, the only reason you're supposed to adjust the power level is to comply with country limitations.  Since devices typically come preconfigured for the country they will be used in, you should normally never need to change this setting.