Linux CPU usage

If you use the task manager in Windows to view the status of each process, you can see that the total CPU usage of the system is the sum of processes.

However, this is not the case when top or other tools are used in Linux. There are often processes with a very high CPU usage up to 90%, but the system's CPU usage is still very low, I don't know why?

I found some information on the Internet to check how the CPU usage in Linux is counted. I think the CPU usage of the system should be the sum of processes,

It's strange. I don't understand it.

Confused ....