My understanding is that those numbers are just artifacts of the third-party status portal software—and not something that Fly.io intends you to take very seriously. (I don’t speak for Fly.io at all, but this is based on what they’ve said themselves in the past.)
Basically, what they do want from the status page is a real-time messaging box, with some ability to view previous messages. These are written in the heat of the moment—while people are still heads-down in debugging and bringing systems back to life—and no one is going to completely nail the exact wording, beginning and ending times, particular list of affected subcomponents, etc., under such circumstances.
For now, the only way to get an idea of overall platform reliability is qualitatively, by reading the prose in the Infrastructure Log. In contrast to the previous paragraph, this one is written in the calm and reflection of a week or more’s distance after the event, 
, having collated everyone’s views, examined internal logs and monitoring feeds, thought extensively about who would have been affected and how, and then assembled a consensus plan for avoiding such problems in the future.
Some day, this will be complemented by an actual, credible numerical graph, based on automatically collected and reported, objective system measurements. The new (and excellent) capacity API is a small step in that direction. (Although obviously some generous soul would need to set up a Machine to poll it every 10 minutes, so there’s readily available history on tap.)
No one is super-happy with the status quo, but hopefully this clears things up a bit!