There are limits on working hours, but I guess the reason is obvious as elsewhere. You have your team of 20+ developers/sysadmins working Mon-Fri, 9am-5pm, and

There are limits on working hours, but I guess the reason is obvious as elsewhere. You have your team of 20+ developers/sysadmins working Mon-Fri, 9am-5pm, and then you have a single individual responding to on-call events outside those hours.