From 3.5 to 3.6, health metric is more detailed and seperated.
I think metric is calculated by authentication and association in 3.5.
Otherwise, In 3.6, metric is calcualted by more factor such as association, authentication, dhcp, eap.
If in 3.6 percent of failed dhcp packet is increase, metric would be more higher than 3.5's
If it is a bit fixed, the metric will be great to check health.
Regards.