That is not how "procd" works: it does not need to check if the process is running, because "procd" is the parent, and gets signaled when the child ends.

From what I read yesterday, the defaults of 3600 5 5 mean if it fails more than 5 times in 3600 seconds, consider it crashed and give up. By setting 3600 to 0, I think it will always try to restart without giving up. I’m not 100% sure of my interpretation though.