I'm pretty sure that Gary Cooper (Aaron's dad) along with Keith Stark and Allen Hartley have all been involved with the tuning since Gary started running the car several years ago. So you would need to ask Gary about the reason for the uptick in performance. Gary has been running an A/F car for along time himself, though. NHRA tech came over to their car and certifed it after the run, so it appears that Aaron Cooper AND Crew are the new MPH record holders.
And had the nitro TAD's not been continuously neutered and strapped with extra weight over the years they'd be in the 4s at 300. NHRA wasn't on board with that and it's probably for the best, anyway. A 5-teen, mid-280 number is still one hell of a ride.