Within an AWS availability zone, how accurate is NTP sync/Chrony in units of microseconds across different aws EC2 instances

These two part blog posts explain the concept of time management on AWS : https://aws.amazon.com/blogs/mt/manage-amazon-ec2-instance-clock-accuracy-using-amazon-time-sync-service-and-amazon-cloudwatch-part-1/

As it is explained, you cannot have a uniform accuracy across all EC2 instances and it has to b measured on the instance (Part 2 explains the process).