Yes, but there are a some more nuances. I'll bet a fair amount of downtime is scheduled, and would be scheduled for low usage periods. Second, most services I'v

Yes, but there are a some more nuances. I'll bet a fair amount of downtime is scheduled, and would be scheduled for low usage periods. Second, most services I've ever used with an SLA for n sixes hasn't actually lived up to that SLA. Instead they offer you a prorated charge for that month or something similar. What people promise in an SLA and what they deliver are very different things. I'd be very interested in some stats about historic uptimes for similar sites. Also, how much more are you willing to pay for an extra 9 of uptime?