please file the ticket in Jira, afaict the stats is not that good maintained consistently during most of the changes. as always, patch is welcome.
Now that things have settled down a bit since ATS v5.0 I wanted to bring this up as I actually use these numbers pretty often to "keep an eye" on TrafficServer.
I can't speak for all of these, but I've noticed over time when viewing stats through traffic_top the "DNS lookup" stat will happily persist through a restart but at the very least "DNS hits" and "DNS Hit" will not.
I'm not really sure what the scoop with "DNS Time" is...for me it's always 0.0. :(
What can I do to help get this resolved eventually?