Double-stacking the pans? Is it necessary?

There's always a debate going on somewhere...the question I've been pondering upon for awhile (even more than my schoolwork...) "Is it necessary to double stack the baking pans?"

I used to think that it didn't matter...but that was until after I baked at my workplace, and there is already a pan in the oven, so the heat distributes more evenly when baking the cupcakes at work. The ones that I baked there turned out so beautifully. The insides were so moist, fluffy, and cake-like. The shell was just crisp enough to give way to a fluffy inner center. I always thought the macaron was such an interesting dessert, and it has many different textures to it that make it unique to a macaron.

So I have always baked with only one pan, and it always seems to have air pockets. Especially if they're not good quality pans, like Farberware...the ones at my work are Nordic Ware. I feel so sad when my macaron looks so pretty on the outside, but ghastly hollow on the inside.  But just this weekend, I tested out my baking pans, and the insides were much more fluffy than usual because I double stacked them. Now my Nordic Ware pans are coming in the mail, so hopefully I can test them at home and be as successful as I was at work :)