Box 1: 5 -
The maximum 5 will kept as the CPU Usage >= 30.
Box 2: 3 -
As soon as the average CPU usage drops below 30%, the count will decrease by 1. After the 5 minute cool-down it will decrease by another 1, reaching 3.
Reference:
https://docs.microsoft.com/en-us/azure/azure-monitor/learn/tutorial-autoscale-performance-schedule