Activity monitor's 'per app' view shows "percentage of one core" which a really odd way to do it, to my mind.
This means that on a 4-core CPU with Hyperthreading, you are seeing what appears to be 8 times the actual load. The User total underneath is [imo] correctly showing the composite total load on the entire CPU.
The "percentage of one core" value is why you see many posts claiming xxx process is using 500% of my CPU