is a dyno not a dyno? lol. whats the difference?
Sadly not mate, they vary massively in the results they will give for the same car.
And even on the same dyno, if the operator wants to there are normally ways to effect the outcome.
Adding 10bhp to a cars output by placing the temp sensor somewhere inappropriate, or fudging the baro settings or strapping the car down is easy enough.
A dyno operator who wants to can easily show you categorically on his dyno that your car definately had another 10bhp since you fitted the air freshener he told you to.
Take it all with a pinch of salt unless you know and trust the operator and are comparing 2 cars from the same dyno.