This fellow can't do the simple math to calculate fliewheel horsepower even if he had the correct drivetrain loss coefficient. This is one of the reasons why fliewheel horsepower shouldn't be used unless we're talking about an engine dyno.
I'm not trying to bag on the fella, math isn't my thing either - the point being is that this whole concept introduces a subjective element into the horsepower conversation to the detriment of everyone's understanding.