I too see the same problem but it looks like the new WU page is the correct one. For me the new WU page matches my exact location according to this neat web map tool. Move the red marker to your location, then read results in box on the right.
http://suncalc.net/Maybe the old WU page is not precise enough and is just going by a general area. Or the difference may be on how each site defines sunset. For example is sunset time reported when sunset starts or when the sun fully sets? So maybe neither are wrong, as one is reporting sunset start and the other is reporting when the sun sets completely.