Reply

You may contact NVC. See the following at:

https://travel.state.gov/content/visas/en/immigrate/immigrant-process/documents/fees/nvc-fee-payment-faqs.html

I paid the AOS fee for one case; do I have to pay the same fee for my other cases?

You must pay the Affidavit of Support fee for each case unless you are a U.S. citizen with petitions for your spouse and/or child(ren)  concurrently in process at NVC.