Same dough. Same oven. Same bake time. The only thing I changed was the oven rack and it changed the final cookie.
Why? Because where your pan sits changes how much heat reaches it from the oven walls, heating elements, hot air, and the baking sheet itself.
Bottom rack = more heat from below, more browning, crispier bottoms, deeper toasted flavor.
Top rack = slower heating from below, often more spread, softer texture, and less browned flavor.
Middle rack = the most balanced heat, which is why so many cookie recipes default to it.
A few inches in your oven can make a bigger difference than you think.
Would you choose top, middle, or bottom?
9/22 Edited to