99% uptime in a year gives you 3.65 days of downtime, which I think would still be within SLA (assuming nothing else happened this year). Though, once you get to 1 9 reliability (99.9%), you've got a shift and change you can be down before you breach SLA.

If their reliability metrics are monthly, 99% gets you less than a shift of down time, so they'd be out of SLA and could probably yell to get money back.