I don't agree. Both measurements and my hearing tells me that overall, the Momentum is nicely balanced and on the neutral side. I've not spent enough time with the K550 to compare but the Momentum is closer to neutral than let's say the HD 800. Or the AKG K701.
Many headphones today have a sound that's a bit on the colder side. Brighter and thinner headphones seem to be perceived as cleaner and more detailed by many. That was my impression of the HD 800 at first. But comparing them to STAX (my reference) the Momentum is closer than the HD 800.
I hear what you're saying. It's all subjective. Different ears, different... strokes?