I've recently purchased the 13" sleeve for my unibody MB and I'm finding that I really have to tug at it to fit it in. Is this sleeve suppose to fit really snug when its brand new and then gradually stretch to form its shape over time? I compared mine to one that my friend has been using and I noticed that my case is 1" shorter in length. I can fit my MB in his sleeve perfectly where as for my case, the MB would stick out at the corners. Is this a problem among the recent batch of incase sleeves? Or have they always fit like that? I'm just worried that if it fits this tight that the zippers would scratch my MB. What are your thoughts on this?