This is such a small, small thing I almost hate to mention it.
When I set up my account and chose a time zone for the offset- there is no selection for Arizona.
We do not observe daylight savings so we kind of have our own time zone thing usually (like say when you set up an OS)
The people I really wonder about are the folks in Indiana who don't do it either- or the part of AZ that does observe it. I guess they are just left out since they are such small groups.