I suppose all outages are just elevated latency. Has anyone ever had an outage and said "fuck it, we're going out of business" and never came back up? That's the only true outage ;)
5xx errors are servers or proxies giving up on requests. Increased timeouts resulting in successful requests may have been considered "elevated latency" (but rarely this would be a proper way to solve similar issue).
They treat 5xx errors as non-errors but this is not the case with rest of the world. "Increased timeouts" is Amazon's untruthful term for "not working at all".