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Question: Mutha Hubba vestibule

I'm confused about vestibule size for the Mutha which I am thinking to purchase soon. I own a nearly worn-out Hubba Hubba whose vestibule is said to be 17.5 ft-sq. This seems small to me. MSR says the Mutha has a 14 ft-sq vestibule. Is that 14 at each end? Otherwise, must be very small. Can anyone set me straight?