I tried on the denim skirt (in petite, mind you) and the size 4 was too big. They did not have it in a 2 to compare, but I suspect that would've fit me. San, you are going to love this skirt, it's really nice. I think you also should try the ponte knit skirt - sooooo comfy!
It does seem to me that AT has redone their fit, not necessarily their sizing. Sizing seems about the same to me as always, though I have gone up a little with weight gain, putting me in the awkward between-sizes area. However, it used to be I could never wear their skirts OR their pants, they would be too tight in the waist and way too loose in the hips. Which is why I'd opt for ATL instead, since they had more of a junior cut. But that is no longer the case at AT - I found lots of their skirts and pants work for me now.