Yes, the impact on rural routes is very real. Especially since they often close earlier -- and if I drive a few miles east, I'm in a different time zone, which penalizes me an hour.
I learned the hard way NOT to do the shops returning west. I will never, ever forget the two post offices I happened to visit exactly 1 hour apart -- but one was in the later timezone, and one was in my home time zone.
I had a really, really difficult time convincing the MSC I was not turning in two reports stating I was in two different places at exactly the same time!!!!