Still, I feel like an idiot, and it's not going to endear me to the client any. I made the mistake I'm always railing at others for making, assuming that because the computer says so, it must be true. You've always got to validate the model somehow against real-world data before you can sign off on it.
I need to get a good night's sleep tonight, as I'm running The Merril Collection SF Flea Market tomorrow and have to get there bright and early. I think I'll be able to sleep properly tonight now.