I am seeing around 100 + checks per minute.
I guess you are getting mixed with application traffic and monitoring traffic. Your logic seems to be good, Interval is 60 seconds and timeout is 300 sec as per your requirement.
- Monitoring traffic comes on a Non-floating Self IP.
- Application Traffic comes on floating Self IP.
The simple way to know to how your monitoring is working is to enable monitor logging. That would show you the timestamps of GET query and response it gets.
When you enable monitor logging, it gets saved in /var/log/monitors/ directory.