ATW got back to me and said they are sending me a sample of their Espresso WPI to compare to what I have.
In the mean time, I'm going to make two shakes at some point. One with Cupcake Batter, and one with Espresso, and try a sip of each back and forth to compare. I swear the tastes are identical from the two shakes I've had today (one in milk, one in water).
Steven from ATW (generously) shipped another 1.25lb bag to me to test for flavor caparison to my other bag. I had hoped for a completely different taste, but unfortunately it is exactly the same as my previous bag.
I want to make something clear, though. This flavor is not "bad" to me, it just has absolutely zero coffee flavor of any kind. ATW claims they have had amazing reviews on the product, and it appears I am the only one that feels that it is lacking in this flavor. As a coffee lover, and former Mocha Joe (Muscle Milk) addict, I can tell you that I indeed know what coffee tastes like. So regardless, I will use all of this protein, it just wont fit into my morning shakes like I had hoped.
Thanks again to Steven and Marc at ATW for their great service.