yeah the RR is more likely to be out, most RR's seem to give generous readings to give the customer a great sense of well being 
also by touching the brakes when the car is winding down on the RR will make the peak bhp higher due to incorrect trans. loss

also by touching the brakes when the car is winding down on the RR will make the peak bhp higher due to incorrect trans. loss
yep always worth a laugh