Hmmm. Areas of Florida, and Texas have higher out door humidity then you do. And they can get their humidity lower the 55%.
Since your paying for it. You get the printed out loads. Sensible and latent. See what it says.
Not saying your running into this. But, contractors in an area know each other. And if this one is a friend of the one that installed your system. He may fudge the load calc.
Its real easy to make it say a half ton more or less the what is already installed.
The infiltration rate value does that real easy. So look close at it.