Just want to add my 2 cents about the Momentum On-ears. For people with smaller ears the sound sig is quite a bit different due to the fit. My ears are completely engulfed in the Momentums but the for MOE they (minus the lobes) can actually fit inside. For me the MOE fit like how the Momentums fit people with larger ears. Not saying that they are uncomfortable, because they are extremely comfortable, even with glasses. Anyway, using Accudio with the balanced settings for the Momentum, the MOE sound inf-ingcredible! In fact, the MOE have superior 'space' in comparison to the Momentums. To my ears anyway.
Looking at the curves, they are pretty similar. However graphs don't tell the whole story, people's ears do. YMMV. In my opinion, the differences is contributed to the cup size and materials used in the padding.