Or couldn't he have ignored the drop of two and relied on the one not changing rate?? Instead there is 'Disagree' when one might have been 'reliable'?? That one could remain servicable but be dropped as a disagreeble partner means there aren't actually three independent samplers?? IOW, could a 'pair' be 1,1a, where a is two seconds ago, meaning consistency? After all, stability can be sampled as well as rate of change, or fault.