Correction, 4:05 p.m. PST: The name of the senior product manager for Google Apps was misspelled. It is Rajen Sheth. Also, Pingdom had an incorrect number for total downtime in its "more likely" scenario. It is 55 minutes.
Pingdom, a company that monitors Web site availability, has concluded that Google gives itself a lot of wiggle room in its service level agreement for its Google Apps service.