I had almost the exact same issue as you, LaJumpa. Let me respond so that I can help you and anyone else who needs help:
My husband (green card holder) and I recently moved. We submitted the AR-11 and I-865 by certified mail. I just got the I-797C, Notice of Action confirming they received my I-865. I was listed as the Petitioner and Sponsor. I believe Crazy Cat is correct. I am the beneficiary of the I-865 as well as the petitioner. My husband's A# was written in small type above my name in both the Petitioner and Beneficiary boxes.
I have received no confirmation that the AR-11 was processed, except for receiving the certified mail return receipt. I called USCIS at the number on the notice of action form, 800–375–5283. I also received the automated response and was unable to speak with an agent. After calling multiple times I decided to try to change my husband's address online. All you have to do is log into the USCIS account. At first I didn't know what to do because he doesn't have a pending case. You need to click on "myUSCIS" where it says "Apply for immigration benefits..." On the next screen you should see a box that says "Change your address". Then fill out that form and it will be recorded. I hope that helps.