vamsi..
AR11 is mandatory for every non-citizen to report change of address to USCIS. Reporting change of address to NSC is totally different and independent issue, you are doing that because you have a pending I485 case with NSC. Since both of you have different 485 applications, you should request COA for both the applications. You can call or send a letter, calling them is the quickest way to report change of address. Mention LIN numbers for all applications pending.