Following instructions are provided without any warranty, and may even get you in trouble legally. The instructions are provided for testing, learning, preventing e-waste, and should be use with care. We (including contributers + commentators) are not responsible for any damage to your device(s) or any legal issues.
Instructions have been moved to https://github.com/francoism90/asus-router. :)
If you go into the router's gui you can, in Wireless Professional settings for 2.4GHz, change the slider at the bottom of the page to Power Save. After reboot the radio output power should be back close to default settings - in my case 17.0 17.0 17.0. This leaves you free to change the radio power without having to edit the wl script.