The flywheel is always an estimated figure. rolling road garages often have different estimates about how much power is lost inbetween the flywheel and the wheels. It will also vary on whether the car is FWD, RWD or 4WD (IIRC FWD suffers the lowest losses, RWD is in the middle and 4WD suffers the highest power losses - due to the number of mechanical linkages the power has to run though driveshafts/diffs etc). The only thing you can take as being accurate and a fair measure is the power taken from the dyno at the front wheels. What was that recorded at? They should of given you a wheel reading as they just add their estimate in order to calculate the flywheel power to that? I think the only way to accurately measure the power at the flywheel is to take the engine out of the car and test it separately on an engine dyno
Lots of people don't like giving the wheel power as its always a smaller figure and not so good for pub chat. Though it is the most meaningful one, as at the end of the day the wheels are the things putting the power down not the fly.