I'm still a bit confused on dress code. They say "professional casual" on the website...When you say business, does that mean business professional (suit) or business casual (slacks/skirt/dress/blazer)?
whatever you would wear to work if you worked at Initech. I don't think there's anything wrong with suit and tie level. Don't stress. You're not being interviewed. Chances are they won't remember you unless you wear a clown costume or something.