Tesla Motors Club

During January, I made daily observations using the dashboard Nav showing the U.S. contiguous states. These sites went down for the first time, during the month:
Supposedly, Tesla will not report any outages if they are beyond a 24 hour navigable drive to the affected locations. So I'm limiting myself to an arc of the U.S. that covers some 50% of the contiguous land mass centered on Houston. In that space are approximately 181 supercharger sites (from what SuperCharge.info tells me). Now my method, was to look for any Nav-reported sites that have the distinctive 'banned' icon (circle with bar) -- and these are symbolically attached to sites that are either temporarily closed or operating on 'reduced service'. I did this only once daily, usually around 8AM central time, so it is entirely possible I missed transient outages, perhaps caused by a local blackout.

I assume, that for a surprise outage to occur, while 'en route', the outage would manifest on the Nav screen during a 2 hours period after a hypothetical car commits to a drive to that SuperCharger site. So the above, 4 sites, had a 'surprise' window of a combined 8 hours. There were 744 hours in January, and about 177 sites that did not 'surprise'. Multiplying 744 x 177 = 131,688 unsurprising site hours. This leaves 8/131,688 or 0.006% chance that a SuperCharger manifest itself as temporary-closure/reduced-service. For this exercise, I assume that all supercharger sites are equally likely to be destinations/way-points.

Please comment if my figures are reasonably in the ball-park for outages (excluding hurricanes, earthquakes, volcanos, meteor strikes and X-class solar flares). Given the small dataset, a wild negative variation might (possibly) be double the hazard... so maybe 0.012% risk, assuming I happened to catch Tesla on a good month?