Why are times different between my two Macbook Pros?

I have two laptops - a 2015 MBP and a 2019 MBP.

Both running Catalina.

Both are configured to "Set date and time automatically" with Cupertino, CA set as the Closest City.

Both have /etc/ntp.conf with the following entry:

server time.apple.com

But the times on the clocks are approximately 2 minutes different. Not that big of a deal, but why would that be the case?