I received a small plate back signed after a couple months (it is racing season!) from this address:
Michael Andretti
Andretti Autosport
7615 Zionsville Road
Indianapolis, IN 46268
USA

I received a small plate back signed. Only took a couple weeks to get back. I used the MA 500, Inc.
457 Rose Inn Ave., Nazareth, PA 18064-9234 address.

I received a small plate signed by Darrell after about a month on 09/14/2021. I used the Deerfield Ct. address.