The resorts don't serve the same pizza. Pizzas at Puck's are considered individual servings. The large 2 credit pizzas at the resorts are considered two servings.
The last time I had a pizza at Puck's Express (barbecue chicken) I thought it had problems - soggy crust, dry chicken. I will not be ordering another pizza there.
Also, pizzas in food courts are only two CS credits if you order them at the food court and either eat them there or carry them out yourself. If you have pizza delivered to your room, it's two TS credits.