Here's the scenario:
Address 1 is my sister's house that I used as the "Mailing Address" on Form I-751 ROC.
Address 2 is me and my husbands (old) "Physical Address" that we put on Form I-751 ROC.
Reason why I used Address 1 as the mailing address was because we were really close to moving out that we didn't have an exact (new) Physical Address to provide.
Anyway, my new address will now be both our "Mailing Address and Physical Address".
When submitting an Address Change to USCIS, which one should we change it from, would the Mailing address be considered the old address or the Physical address that was used on the I-751? I want to make sure we receive any form of letters, receipts, notices to my new address. I just don't know which address should we consider as "old address". Any help would be greatly appreciated!