According to the Tool-Tip (and pretty sure it worked that way before), Energetic Dance-Style should push Hardcore appeal and lower Casual Appeal, notthe other way around as it appears here.
Casual and Hardcore appeal are now also affected by the current popularity of that genre / lyrics theme / dance style (check the sales chart), so it's probably because of that.
Popular dance style = bonus to casual and penalty to hardcore, unpopular = bonus to hardcore and penalty to casual.
