Mich: Just as a longer draw gets more performance out of a bow by flexing the limbs more, a shorter draw will flex the limbs of a shorter bow more than it will a longer bow, providing a bit more energy. Not talking big differences here, but they are real.
Of course, limb design and materials have more effect on performance than length, but in this case, the bows would be identical except for length.
Just as my "probably" is a qualifier, your "usually" is too. Longer bows aren't necessarily smoother, quieter either. Depends on design, materials, etc. but that's the way to bet. At a 27 inch draw, those differences will be small, too, between two inches of bow length, all other things being equal