What's acceptable risk
The graphs from ATSB show Jabiru well in the lead when it comes to rate per 000's. If you take Jabiru out of the equation there will always be a particular engine that will be less reliable than others. So, what is the acceptable risk of failure for any one of these engines? Until CASA locks itself into a position of acceptable risk on this matter, this argument could go on forever with the ever changing goalposts afforded by being non-committal.