Yeap...it's only one per month per party....and this is tracked when you redeem them. Only way around it is to purchase the two certs using two different accounts on Restaurants.com, using two different credit cards...and split you party into two un-connected partys that will not talk to each other at the restaurant. I'm just guessing on that..really I am.
By the way....love to food and atmosphere at HOB. Ate there last Aug..and will try to go again in Dec.