Channel Width in LuCI

The drop down list has 20, 40, and 80. I don't see 20/40 or 20/40/80. Does selecting 40 automatically give you 20/40 or does selecting 80 give you 20/40/80?

I'd guess it would depend on the actual device, but some information about values available here: https://wiki.openwrt.org/doc/uci/wireless#mac80211_device_options. You can check the /etc/config/wireless file after setting values with Luci.

hostapd automatically downgrades. You are not setiing the channels bandwith so much as you are setting the MAXIMUM it will go up to.

Thank you.