I don't know the Netflix contract but I've been involved with a few big (telco) SLAs. The penalties are usually calculated with a points-system and a multiplier

I don't know the Netflix contract but I've been involved with a few big (telco) SLAs. The penalties are usually calculated with a points-system and a multiplier that raises according to the duration/impact of an outage. E.g. the first 15 minutes of an outage may cost 1 point per minute, 15-60 minutes 2 points, and so on. You also have multipliers for the severity (partial or full outage, customer impact, affected countries, etc.), time-of-day, and so on. Collected points may then later be traded in for dollars or a nice lawsuit. Corporate lawyers love to go nuts on these things, an enterprise SLA can easily span a hundred pages of legalese.