Can I first correct you on two major errors in your statement. TWO AOA vanes are NOT an option on any aircraft. Every aircraft have two vanes as standard. the option is for a small AOA position indicator icon on the top corner on the main screen for the captains side. also there is no AOA disagree light. This is an amber AOA disagree text that appears on the screen. I can only say that on my airline this is standard as it was on the 737 NG in our fleet.