He’s telling the truth we have this same problem driving with amazon it’s an ongoing problem. I’ve always ask the customer if they still want it with the broken box they usually take it but often times they say send it back
i would take it to a dyno and test those numbers, to be at 500-550 and not be on e85 is pretty intense, let alone just on street flashing. im not saying he lying, but i think their could be some errors