FWIW: I have dyno'd/tuned 200+ different vehicles. Its a rare occasion when a high HP car duplicates its number on two different dyno pulls. IE: most cars will vary a few WHP from pull to pull, or dyno to dyno. 13WHP is almost insignificant and within the margin of error on a 300-400WHP car. And a 350WHP car is making more than that moving down the track as well.