You might be right about ATs being a 4bet/fold. I'd edge toward folding because I block too much of his folding range which will be like TT, 9-AT but off the top of my head I don't know. To I quite happily fold and ATs is the worst Ace I call in that spot would be a very easy fold against most players at 2nl zoom just a poor adjustment on my part and probably tilt creeping in after a crappy day at the tables.