And here is the order and authorization from FCC that gave them permission to do that launch, including deploying 10 Starlink satellites at 560km:

https://docs.fcc.gov/public/attachments/DA-21-34A1.pdf

Note that SpaceX asked for more, but FCC decided to only grant 10 satellites for now. So, SpaceX did as they always do and followed the order to the letter, and only deployed 10.