You’re not crazy. Those combination fast food joints — like Taco Bell combination Pizza Hut and Papa John’s combination Subway — are grosser than their individual counterparts, and Ben Wellington of I Quant NY has the data to prove it.
White Castle is the best, followed by Taco Bell, Starbucks, Pizza Hut. The worst by far is IHOP, followed by Papa John’s and Domino’s Pizza.
Different types of food preparation may lead to different numbers of violations, and IHOP has the most varied menu of all the options above. The same could be true for combo-chains: more food options means more things can go wrong. But thousands of restaurants across New York City are able to maintain an A score, and I guarantee that they all have more complicated menus than any of these chains.