WC
So you didn't like the report much
There seemed to be an itsy bitsy over representation of Mooneys (9 from a small sample of 33) and a desire (that I did not understand) to relate the numbers to a 6 hour mission, which strikes me as unusually long for an SEP, even in the States where some people do use them for business trips. In fact, I wonder how many of the types listed could legally file a 6 hour IFR (or even VFR) flight with a full pax load or even at gross weight with pax offloaded for fuel? I'd be very surprised if this list included the 152 and the 172 - some of the others might just do it with long range tanks, but not with me as P1! (not just for safety reasons either - how ling can the average middle aged bladder hold out for?
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I'd guess that the average sector for a single is about 1hr, maybe 90 mins. I haven't read the report methodology properly, but in the real world I'd expect less stress and strain on an engine flying 6 hour sectors (with a long cruise segment at stable air temperatures and power settings) - especially the turbo variety and this would impact on the reliability in itself, although to what degree I don't profess to have a view.
At the end of the day, I prepare for engine failure every time I fly and just hope I never have to demonstrate my 'superior' skills!