@Karnali9 we did not submit any cover letter. Not sure if submitting any cover letter is helpful either unless requested. I feel like that would be like pointing them out to the "problem" although it probably really isn't a problem. I don't remember how exactly we filled out forms but I remember using same mailing address for both of us so all communication from USCIS were sent to same address and visits to USCIS were scheduled at the USCIS location closer to that mailing address.