Yes, the radio schedule controls the availability of your wireless connection and is meant for those in primarily wired area who don't care much about who gets cut off.
To answer your first question, the radio will kick you off without warnings, according to the changes you have set up.
For your second question, I couldn't find the exact setting page from your Wifi snapshot under my own version (
v.24 std DD-WRT for 2/2011) and advanced Wireless only describes channel and encryption settings, rather than a schedule.
I would guess that it doesn't matter that you found a settings page enable your wireless manually, because another will still "remember" your schedule and power things off at the appointed time. It is up to your router to handle that.