Bob's Burgers is doing slightly better than American Dad's 7:30 ratings. Compare Bob's Burgers to AD's ratings at 9:30 and it falls apart, because AD was pulling like ~2.7s there while Bob's Burgers gets around a 2.1. I know they're still two different timeslots but 8:30 and 9:30 are both within the "regular" block while the 7:00 hour is really just holdover.
Like I said, AD isn't being judged based on its 7:30 performance, but on its 9:30 performance in the fall.