The way I see it, you should still just cook like you were only cooking one turkey, I mean they're both the same weight, and they're both in the same temp, but that second bird is gonna absorb heat, this is a REAL question!!! Now I gotta know!!
If you put two ten pounds of turkey in the same oven, you will need to stick to the same cooking time like for one 10lb turkey. Cook the turkeys for two and a half hours or three hours if they are stuffed.