Yes it looks like a duel edge design, but it's not. Laws very by jurisdiction and I don't know where you live, but I'd bet even money that a dual edged weapon is looked at differently than a single edged knife legally in your city/state. Maybe Benchmade doesn't want to get mixed up in any potential legal issues that may arise from providing you with such a knife?
Or, maybe asking to have your knife customized for $5 was just a little presumptuous (one might even say odd) on your part?
"Gratitude is riches, complaint is poverty, and the worse I ever had was wonderful"